Efiwe: SQL Dictionary

Keyword/Function	Belongs To	Description
`ADD`	SQL Keywords	Adds a new column to an existing table. Introduced in: SQL → Level 1 → Challenge 8
`ADD CONSTRAINT`	SQL Keywords	Adds a constraint to a table after the table has already been created.
`ALL`	SQL Keywords	Used with a subquery — evaluates to true only if every value returned by the subquery satisfies the condition. Introduced in: SQL → Level 1 → Challenge 7
`ALTER`	SQL Keywords	Adds, removes, or modifies columns in a table, or changes a column's data type. Introduced in: SQL → Level 1 → Challenge 11
`ALTER COLUMN`	SQL Keywords	Changes the data type of an existing column in a table.
`ALTER TABLE`	SQL Keywords	Adds, removes, or modifies the columns of an existing table. Introduced in: SQL → Level 1 → Challenge 11
`ALTER VIEW`	SQL Keywords	Redefines an existing view.
`AND`	SQL Keywords	Combines two conditions in a WHERE clause — a row only qualifies if both are true. Introduced in: SQL → Level 1 → Challenge 1
`ANY`	SQL Keywords	Used with a subquery — evaluates to true if at least one value returned by the subquery satisfies the condition. Introduced in: SQL → Level 1 → Challenge 11
`AS`	SQL Keywords	Gives a column or table a temporary alias for the duration of the query. Introduced in: SQL → Level 1 → Challenge 4
`ASC`	SQL Keywords	Sorts query results in ascending order (the default sort direction). Introduced in: SQL → Level 1 → Challenge 27
`BACKUP DATABASE`	SQL Keywords	Creates a backup copy of an existing database.
`BETWEEN`	SQL Keywords	Filters results to values that fall within a specified inclusive range. Introduced in: SQL → Level 1 → Challenge 10
`CASE`	SQL Keywords	Returns different output values depending on which of several conditions is met. Introduced in: SQL → Level 2 → Challenge 92
`CHECK`	SQL Keywords	A constraint that restricts the values allowed in a column. Introduced in: SQL → Level 2 → Challenge 76
`COLUMN`	SQL Keywords	Refers to changing the data type of a column, or deleting a column, within a table. Introduced in: SQL → Level 1 → Challenge 1
`CONSTRAINT`	SQL Keywords	Adds or removes a rule that restricts the data allowed in a table. Introduced in: SQL → Level 3 → Challenge 101
`CREATE`	SQL Keywords	Creates a new database object — a database, table, index, view, or procedure. Introduced in: SQL → Level 1 → Challenge 7
`CREATE DATABASE`	SQL Keywords	Creates a brand-new SQL database.
`CREATE INDEX`	SQL Keywords	Builds an index on a table's column(s) to speed up lookups; duplicate values are allowed. Introduced in: SQL → Level 3 → Challenge 109
`CREATE OR REPLACE VIEW`	SQL Keywords	Creates a view, or overwrites it if a view with that name already exists. Introduced in: SQL → Level 5 → Challenge 231
`CREATE TABLE`	SQL Keywords	Creates a new table with the specified columns in the database. Introduced in: SQL → Level 1 → Challenge 7
`CREATE PROCEDURE`	SQL Keywords	Defines a new stored procedure — a saved, reusable block of SQL.
`CREATE UNIQUE INDEX`	SQL Keywords	Builds an index that also enforces that every value in the indexed column(s) is unique. Introduced in: SQL → Level 3 → Challenge 107
`CREATE VIEW`	SQL Keywords	Creates a virtual table (a view) based on the result set of a SELECT statement. Introduced in: SQL → Level 2 → Challenge 96
`DATABASE`	SQL Keywords	Refers to creating or deleting an SQL database. Introduced in: SQL → Level 1 → Challenge 1
`DEFAULT`	SQL Keywords	A constraint that supplies a fallback value for a column when none is provided. Introduced in: SQL → Level 1 → Challenge 26
`DELETE`	SQL Keywords	Removes one or more existing rows from a table. Introduced in: SQL → Level 3 → Challenge 143
`DESC`	SQL Keywords	Sorts query results in descending order. Introduced in: SQL → Level 1 → Challenge 27
`DISTINCT`	SQL Keywords	Removes duplicate rows from the result set, keeping only unique values. Introduced in: SQL → Level 1 → Challenge 32
`DROP`	SQL Keywords	Permanently removes a database object — a column, constraint, database, index, table, or view. Introduced in: SQL → Level 2 → Challenge 100
`DROP COLUMN`	SQL Keywords	Permanently removes a column from a table. Introduced in: SQL → Level 5 → Challenge 228
`DROP CONSTRAINT`	SQL Keywords	Removes a UNIQUE, PRIMARY KEY, FOREIGN KEY, or CHECK constraint from a table.
`DROP DATABASE`	SQL Keywords	Permanently deletes an entire database.
`DROP DEFAULT`	SQL Keywords	Removes a DEFAULT constraint from a column.
`DROP INDEX`	SQL Keywords	Removes an index from a table. Introduced in: SQL → Level 3 → Challenge 112
`DROP TABLE`	SQL Keywords	Permanently deletes a table and all of its data. Introduced in: SQL → Level 3 → Challenge 143
`DROP VIEW`	SQL Keywords	Permanently deletes a view. Introduced in: SQL → Level 2 → Challenge 100
`EXEC`	SQL Keywords	Runs (executes) a stored procedure.
`EXISTS`	SQL Keywords	Tests whether a subquery returns any rows at all. Introduced in: SQL → Level 1 → Challenge 8
`FOREIGN KEY`	SQL Keywords	A constraint that links a column to the primary key of another table. Introduced in: SQL → Level 2 → Challenge 59
`FROM`	SQL Keywords	Specifies which table a query should read from or delete data from. Introduced in: SQL → Level 1 → Challenge 2
`FULL OUTER JOIN`	SQL Keywords	Returns every row from both tables, matching them where possible and filling in NULLs where there's no match. Introduced in: SQL → Level 5 → Challenge 242
`GROUP BY`	SQL Keywords	Groups rows that share the same values, typically so aggregate functions (COUNT, MAX, MIN, SUM, AVG) can be applied per group. Introduced in: SQL → Level 2 → Challenge 51
`HAVING`	SQL Keywords	Filters grouped results — used in place of WHERE when the condition involves an aggregate function. Introduced in: SQL → Level 2 → Challenge 54
`IN`	SQL Keywords	Checks whether a column's value matches any value in a given list. Introduced in: SQL → Level 1 → Challenge 2
`INDEX`	SQL Keywords	Refers to creating or deleting an index on a table. Introduced in: SQL → Level 3 → Challenge 107
`INNER JOIN`	SQL Keywords	Returns only the rows that have matching values in both joined tables. Introduced in: SQL → Level 2 → Challenge 63
`INSERT INTO`	SQL Keywords	Adds one or more new rows of data into a table. Introduced in: SQL → Level 1 → Challenge 8
`INSERT INTO SELECT`	SQL Keywords	Copies rows from one table into another table.
`IS NULL`	SQL Keywords	Tests whether a value is empty (NULL). Introduced in: SQL → Level 1 → Challenge 22
`IS NOT NULL`	SQL Keywords	Tests whether a value is not empty (not NULL). Introduced in: SQL → Level 1 → Challenge 23
`JOIN`	SQL Keywords	Combines rows from two or more tables based on a related column. Introduced in: SQL → Level 2 → Challenge 63
`LEFT JOIN`	SQL Keywords	Returns every row from the left table, plus any matching rows from the right table (NULL where there's no match). Introduced in: SQL → Level 2 → Challenge 67
`LIKE`	SQL Keywords	Filters rows using pattern matching against a column's text. Introduced in: SQL → Level 1 → Challenge 4
`LIMIT`	SQL Keywords	Restricts the number of rows a query returns. Introduced in: SQL → Level 1 → Challenge 29
`NOT`	SQL Keywords	Negates a condition, so only rows where it's false are included. Introduced in: SQL → Level 1 → Challenge 1
`NOT NULL`	SQL Keywords	A constraint that forces a column to always contain a value. Introduced in: SQL → Level 1 → Challenge 23
`OR`	SQL Keywords	Combines two conditions in a WHERE clause — a row qualifies if either one is true. Introduced in: SQL → Level 1 → Challenge 18
`ORDER BY`	SQL Keywords	Sorts the result set by one or more columns, ascending or descending. Introduced in: SQL → Level 1 → Challenge 26
`OUTER JOIN`	SQL Keywords	Returns every row from at least one table involved in the join, even without a match on the other side. Introduced in: SQL → Level 5 → Challenge 242
`PRIMARY KEY`	SQL Keywords	A constraint that uniquely identifies every row in a table. Introduced in: SQL → Level 1 → Challenge 7
`PROCEDURE`	SQL Keywords	Refers to a stored procedure — a saved routine of SQL statements.
`RIGHT JOIN`	SQL Keywords	Returns every row from the right table, plus any matching rows from the left table. Introduced in: SQL → Level 2 → Challenge 73
`ROWNUM`	SQL Keywords	Limits the number of rows returned by a query (Oracle syntax).
`SELECT`	SQL Keywords	Retrieves data from one or more tables. Introduced in: SQL → Level 1 → Challenge 1
`SELECT DISTINCT`	SQL Keywords	Retrieves only the unique values for the selected column(s). Introduced in: SQL → Level 1 → Challenge 32
`SELECT INTO`	SQL Keywords	Copies data from one table into a brand-new table.
`SELECT TOP`	SQL Keywords	Limits the number of rows a query returns (SQL Server / MS Access syntax).
`SET`	SQL Keywords	Specifies which columns to update and what values to assign, inside an UPDATE statement. Introduced in: SQL → Level 1 → Challenge 12
`TABLE`	SQL Keywords	Refers to creating, altering, or dropping a table, or its data. Introduced in: SQL → Level 1 → Challenge 7
`TOP`	SQL Keywords	Limits the number of records a query returns. Introduced in: SQL → Level 1 → Challenge 2
`TRUNCATE TABLE`	SQL Keywords	Empties a table of all its rows while keeping the table structure itself.
`UNION`	SQL Keywords	Combines the results of two or more SELECT statements, keeping only distinct rows. Introduced in: SQL → Level 2 → Challenge 83
`UNION ALL`	SQL Keywords	Combines the results of two or more SELECT statements, keeping duplicate rows too. Introduced in: SQL → Level 2 → Challenge 84
`UNIQUE`	SQL Keywords	A constraint that ensures every value in a column is different from all the others. Introduced in: SQL → Level 1 → Challenge 32
`UPDATE`	SQL Keywords	Modifies the values of existing rows in a table. Introduced in: SQL → Level 1 → Challenge 12
`VALUES`	SQL Keywords	Supplies the actual data to insert, inside an INSERT INTO statement. Introduced in: SQL → Level 1 → Challenge 7
`VIEW`	SQL Keywords	Refers to creating, updating, or deleting a saved virtual table built from a SELECT query. Introduced in: SQL → Level 2 → Challenge 96
`WHERE`	SQL Keywords	Filters a result set down to only the rows that satisfy a given condition. Introduced in: SQL → Level 1 → Challenge 2
`ASCII`	MySQL	Returns the ASCII numeric code of the first character in a string.
`CHAR_LENGTH`	MySQL	Returns how many characters are in a string.
`CHARACTER_LENGTH`	MySQL	An alias for CHAR_LENGTH — returns the character count of a string.
`CONCAT`	MySQL / SQL Server	Joins two or more strings together into one. Introduced in: SQL → Level 2 → Challenge 85
`CONCAT_WS`	MySQL / SQL Server	Joins two or more strings together, inserting a separator between each one.
`FIELD`	MySQL	Returns the 1-based position of a value within a list of values.
`FIND_IN_SET`	MySQL	Returns the position of a string inside a comma-separated list of strings.
`FORMAT`	MySQL	Formats a number with grouped thousands, rounded to a given number of decimals. Introduced in: SQL → Level 2 → Challenge 89
`INSERT`	MySQL	Inserts a substring into a string at a given position, replacing a specified number of characters. Introduced in: SQL → Level 1 → Challenge 8
`INSTR`	MySQL	Returns the position of the first occurrence of a substring inside another string. Introduced in: SQL → Level 3 → Challenge 121
`LCASE`	MySQL	Converts a string to lowercase (alias for LOWER).
`LEFT`	MySQL / SQL Server / MS Access	Extracts a given number of characters from the start (left) of a string. Introduced in: SQL → Level 2 → Challenge 67
`LENGTH`	MySQL	Returns the length of a string in bytes. Introduced in: SQL → Level 1 → Challenge 41
`LOCATE`	MySQL	Returns the position of the first occurrence of a substring within a string.
`LOWER`	MySQL / SQL Server	Converts a string to lowercase. Introduced in: SQL → Level 2 → Challenge 86
`LPAD`	MySQL	Pads a string on the left with another string until it reaches a target length.
`LTRIM`	MySQL / SQL Server / MS Access	Strips leading (left-side) spaces from a string. Introduced in: SQL → Level 3 → Challenge 122
`MID`	MySQL / MS Access	Extracts a substring starting at a given position within a string.
`POSITION`	MySQL	Returns the position of the first occurrence of a substring within a string. Introduced in: SQL → Level 3 → Challenge 120
`REPEAT`	MySQL	Repeats a string a specified number of times.
`REPLACE`	MySQL / SQL Server	Replaces every occurrence of a substring within a string with a new substring. Introduced in: SQL → Level 3 → Challenge 123
`REVERSE`	MySQL / SQL Server	Reverses the order of characters in a string. Introduced in: SQL → Level 2 → Challenge 99
`RIGHT`	MySQL / SQL Server / MS Access	Extracts a given number of characters from the end (right) of a string. Introduced in: SQL → Level 1 → Challenge 11
`RPAD`	MySQL	Pads a string on the right with another string until it reaches a target length.
`RTRIM`	MySQL / SQL Server / MS Access	Strips trailing (right-side) spaces from a string. Introduced in: SQL → Level 3 → Challenge 122
`SPACE`	MySQL / SQL Server / MS Access	Returns a string made up of a specified number of spaces. Introduced in: SQL → Level 5 → Challenge 207
`STRCMP`	MySQL	Compares two strings and returns 0, -1, or 1 depending on how they compare.
`SUBSTR`	MySQL	Extracts a substring starting at a given position (alias for SUBSTRING). Introduced in: SQL → Level 3 → Challenge 120
`SUBSTRING`	MySQL	Extracts a substring from a string, starting at a given position. Introduced in: SQL → Level 3 → Challenge 123
`SUBSTRING_INDEX`	MySQL	Returns the portion of a string that comes before a specified number of delimiter occurrences.
`TRIM`	MySQL	Removes leading and trailing spaces from a string. Introduced in: SQL → Level 3 → Challenge 122
`UCASE`	MySQL	Converts a string to uppercase (alias for UPPER).
`UPPER`	MySQL / SQL Server	Converts a string to uppercase. Introduced in: SQL → Level 2 → Challenge 86
`ABS`	MySQL / SQL Server / MS Access	Returns the absolute (non-negative) value of a number. Introduced in: SQL → Level 3 → Challenge 125
`ACOS`	MySQL / SQL Server	Returns the arc cosine of a number.
`ASIN`	MySQL / SQL Server	Returns the arc sine of a number.
`ATAN`	MySQL	Returns the arc tangent of one number, or of two numbers.
`ATAN2`	MySQL	Returns the arc tangent of two numbers.
`AVG`	MySQL / SQL Server / MS Access	Returns the average value of a numeric expression across a group of rows. Introduced in: SQL → Level 1 → Challenge 46
`CEIL`	MySQL	Rounds a number up to the nearest integer that is greater than or equal to it. Introduced in: SQL → Level 5 → Challenge 212
`CEILING`	MySQL	An alias for CEIL — rounds a number up to the nearest integer.
`COS`	MySQL / SQL Server	Returns the cosine of a number.
`COT`	MySQL / SQL Server	Returns the cotangent of a number.
`COUNT`	MySQL / SQL Server / MS Access	Returns how many rows a SELECT query matched. Introduced in: SQL → Level 1 → Challenge 44
`DEGREES`	MySQL / SQL Server	Converts a value from radians into degrees.
`DIV`	MySQL	Performs integer division, discarding the remainder.
`EXP`	MySQL / SQL Server / MS Access	Returns e (Euler's number) raised to the power of a given number.
`FLOOR`	MySQL / SQL Server	Rounds a number down to the nearest integer that is less than or equal to it. Introduced in: SQL → Level 5 → Challenge 212
`GREATEST`	MySQL	Returns the largest value from a list of arguments.
`LEAST`	MySQL	Returns the smallest value from a list of arguments. Introduced in: SQL → Level 2 → Challenge 58
`LN`	MySQL	Returns the natural logarithm (base e) of a number.
`LOG`	MySQL / SQL Server	Returns the natural logarithm of a number, or its logarithm to a specified base.
`LOG10`	MySQL / SQL Server	Returns the base-10 logarithm of a number.
`LOG2`	MySQL	Returns the base-2 logarithm of a number.
`MAX`	MySQL / SQL Server / MS Access	Returns the largest value in a set of values. Introduced in: SQL → Level 1 → Challenge 47
`MIN`	MySQL / SQL Server / MS Access	Returns the smallest value in a set of values. Introduced in: SQL → Level 1 → Challenge 47
`MOD`	MySQL	Returns the remainder left over after dividing one number by another. Introduced in: SQL → Level 5 → Challenge 214
`PI`	MySQL / SQL Server	Returns the mathematical constant pi.
`POW`	MySQL	Raises a number to the power of another number (alias for POWER).
`POWER`	MySQL / SQL Server	Raises a number to the power of another number. Introduced in: SQL → Level 5 → Challenge 213
`RADIANS`	MySQL / SQL Server	Converts a value from degrees into radians.
`RAND`	MySQL / SQL Server	Returns a random floating-point number.
`ROUND`	MySQL / SQL Server / MS Access	Rounds a number to a specified number of decimal places. Introduced in: SQL → Level 3 → Challenge 124
`SIGN`	MySQL / SQL Server	Returns whether a number is negative (-1), zero (0), or positive (1). Introduced in: SQL → Level 5 → Challenge 208
`SIN`	MySQL / SQL Server	Returns the sine of a number.
`SQRT`	MySQL / SQL Server	Returns the square root of a number. Introduced in: SQL → Level 5 → Challenge 213
`SUM`	MySQL / SQL Server / MS Access	Adds up a set of numeric values. Introduced in: SQL → Level 1 → Challenge 45
`TAN`	MySQL / SQL Server	Returns the tangent of a number.
`TRUNCATE`	MySQL	Truncates a number to a specified number of decimal places, without rounding.
`ADDDATE`	MySQL	Adds a time/date interval to a date and returns the resulting date.
`ADDTIME`	MySQL	Adds a time interval to a time or datetime value.
`CURDATE`	MySQL	Returns today's date.
`CURRENT_DATE`	MySQL	Returns today's date (equivalent to CURDATE).
`CURRENT_TIME`	MySQL	Returns the current time.
`CURRENT_TIMESTAMP`	MySQL	Returns the current date and time together.
`CURTIME`	MySQL	Returns the current time (equivalent to CURRENT_TIME).
`DATE`	MySQL	Extracts just the date portion from a datetime value. Introduced in: SQL → Level 2 → Challenge 89
`DATEDIFF`	MySQL	Returns the number of days between two dates. Introduced in: SQL → Level 5 → Challenge 223
`DATE_ADD`	MySQL	Adds a time/date interval to a date and returns the resulting date.
`DATE_FORMAT`	MySQL	Formats a date according to a specified pattern.
`DATE_SUB`	MySQL	Subtracts a time/date interval from a date and returns the resulting date.
`DAY`	MySQL	Returns the day of the month (1–31) for a given date. Introduced in: SQL → Level 2 → Challenge 90
`DAYNAME`	MySQL	Returns the name of the weekday for a given date (e.g. 'Monday').
`DAYOFMONTH`	MySQL	Returns the day of the month for a given date (alias for DAY).
`DAYOFWEEK`	MySQL	Returns a numeric index for the weekday of a given date.
`DAYOFYEAR`	MySQL	Returns which day of the year a given date falls on (1–366).
`EXTRACT`	MySQL	Pulls a specific part (year, month, day, etc.) out of a date. Introduced in: SQL → Level 5 → Challenge 220
`FROM_DAYS`	MySQL	Converts a day-number value back into a calendar date.
`HOUR`	MySQL / MS Access	Returns the hour portion of a time or datetime value.
`LAST_DAY`	MySQL	Returns the date of the last day of the month for a given date.
`LOCALTIME`	MySQL	Returns the current date and time.
`LOCALTIMESTAMP`	MySQL	Returns the current date and time.
`MAKEDATE`	MySQL	Builds a date from a given year and a number of days into that year.
`MAKETIME`	MySQL	Builds a time value from given hour, minute, and second values.
`MICROSECOND`	MySQL	Returns the microsecond portion of a time or datetime value.
`MINUTE`	MySQL / MS Access	Returns the minute portion of a time or datetime value.
`MONTH`	MySQL	Returns the month (1–12) for a given date. Introduced in: SQL → Level 2 → Challenge 90
`MONTHNAME`	MySQL	Returns the full name of the month for a given date.
`NOW`	MySQL	Returns the current date and time. Introduced in: SQL → Level 1 → Challenge 5
`PERIOD_ADD`	MySQL	Adds a given number of months onto a year-month period value.
`PERIOD_DIFF`	MySQL	Returns the number of months between two year-month period values.
`QUARTER`	MySQL	Returns which quarter of the year (1–4) a given date falls in.
`SECOND`	MySQL / MS Access	Returns the seconds portion of a time or datetime value. Introduced in: SQL → Level 1 → Challenge 2
`SEC_TO_TIME`	MySQL	Converts a number of seconds into a HH:MM:SS time value.
`STR_TO_DATE`	MySQL	Parses a string into a date, using a specified format.
`SUBDATE`	MySQL	Subtracts a time/date interval from a date (alias behavior of DATE_SUB).
`SUBTIME`	MySQL	Subtracts a time interval from a time or datetime value.
`SYSDATE`	MySQL	Returns the current date and time at the moment the function actually executes.
`TIME`	MySQL	Extracts just the time portion from a datetime value. Introduced in: SQL → Level 1 → Challenge 2
`TIME_FORMAT`	MySQL	Formats a time value according to a specified pattern.
`TIME_TO_SEC`	MySQL	Converts a time value into a total number of seconds.
`TIMEDIFF`	MySQL	Returns the difference between two time or datetime values.
`TIMESTAMP`	MySQL	Converts a date, or a date and time, into a single datetime value.
`TO_DAYS`	MySQL	Returns the number of days between a date and the reference date '0000-00-00'.
`WEEK`	MySQL	Returns the week number of the year for a given date. Introduced in: SQL → Level 4 → Challenge 177
`WEEKDAY`	MySQL	Returns a numeric weekday index (0 = Monday) for a given date. Introduced in: SQL → Level 5 → Challenge 224
`WEEKOFYEAR`	MySQL	Returns the calendar week number for a given date.
`YEAR`	MySQL / MS Access	Returns the year portion of a given date. Introduced in: SQL → Level 2 → Challenge 90
`YEARWEEK`	MySQL	Returns the year and week number combined for a given date.
`BIN`	MySQL	Returns the binary representation of a number, as a string.
`BINARY`	MySQL	Converts a value into a binary string for byte-by-byte comparison.
`CASE`	MySQL	Steps through a series of conditions and returns a value for the first one that's true. Introduced in: SQL → Level 2 → Challenge 92
`CAST`	MySQL / SQL Server	Converts a value from one data type into another. Introduced in: SQL → Level 4 → Challenge 180
`COALESCE`	MySQL / SQL Server	Returns the first non-NULL value from a list of expressions. Introduced in: SQL → Level 2 → Challenge 98
`CONNECTION_ID`	MySQL	Returns the unique ID of the current database connection.
`CONV`	MySQL	Converts a number from one numeric base to another (e.g. decimal to hex).
`CONVERT`	MySQL	Converts a value into a specified data type or character set.
`CURRENT_USER`	MySQL	Returns the username and host that authenticated the current session.
`DATABASE`	MySQL	Returns the name of the currently selected database. Introduced in: SQL → Level 1 → Challenge 1
`IF`	MySQL	Returns one value if a condition is true, and another if it's false. Introduced in: SQL → Level 1 → Challenge 33
`IFNULL`	MySQL	Returns a fallback value when an expression is NULL, otherwise returns the expression itself. Introduced in: SQL → Level 4 → Challenge 182
`ISNULL`	MySQL	Returns 1 if an expression is NULL, and 0 otherwise.
`LAST_INSERT_ID`	MySQL	Returns the AUTO_INCREMENT ID generated by the most recent INSERT.
`NULLIF`	MySQL / SQL Server	Compares two expressions and returns NULL if they're equal, otherwise returns the first one. Introduced in: SQL → Level 2 → Challenge 99
`SESSION_USER`	MySQL	Returns the current MySQL username and host (alias for CURRENT_USER).
`SYSTEM_USER`	MySQL	Returns the current MySQL username and host (alias for CURRENT_USER).
`USER`	MySQL	Returns the current MySQL username and host.
`VERSION`	MySQL	Returns the version number of the MySQL server. Introduced in: SQL → Level 3 → Challenge 131
`ASCII`	SQL Server	Returns the ASCII numeric code of a specific character.
`CHAR`	SQL Server	Returns the character that corresponds to a given ASCII code.
`CHARINDEX`	SQL Server	Returns the position of a substring within a string.
`Concat with +`	SQL Server	Uses the + operator between strings to join them together. Introduced in: SQL → Level 2 → Challenge 85
`DATALENGTH`	SQL Server	Returns the number of bytes used to store an expression.
`DIFFERENCE`	SQL Server	Compares the SOUNDEX values of two strings and scores how similar they sound. Introduced in: SQL → Level 5 → Challenge 217
`FORMAT`	SQL Server / MS Access	Formats a value according to a specified display format. Introduced in: SQL → Level 2 → Challenge 89
`LEN`	SQL Server / MS Access	Returns the length of a string.
`NCHAR`	SQL Server	Returns the Unicode character that corresponds to a given number code.
`PATINDEX`	SQL Server	Returns the starting position of a pattern within a string.
`QUOTENAME`	SQL Server	Wraps a string in delimiters so it becomes a valid SQL Server identifier.
`REPLICATE`	SQL Server	Repeats a string a specified number of times.
`SOUNDEX`	SQL Server	Returns a four-character code representing how a string sounds, for fuzzy matching.
`STR`	SQL Server / MS Access	Converts a number into a string.
`STUFF`	SQL Server	Removes part of a string and inserts a replacement, starting at a given position.
`SUBSTRING`	SQL Server	Extracts a specified number of characters from a string, starting at a given position. Introduced in: SQL → Level 3 → Challenge 123
`TRANSLATE`	SQL Server	Replaces a set of characters in a string with a corresponding set of replacement characters. Introduced in: SQL → Level 1 → Challenge 1
`TRIM`	SQL Server	Removes leading and trailing spaces (or other specified characters) from a string. Introduced in: SQL → Level 3 → Challenge 122
`UNICODE`	SQL Server	Returns the Unicode code point of the first character of a string.
`ATAN`	SQL Server	Returns the arc tangent of a number.
`ATN2`	SQL Server	Returns the arc tangent of two numbers.
`CEILING`	SQL Server	Rounds a number up to the nearest integer that is greater than or equal to it.
`SQUARE`	SQL Server	Returns a number multiplied by itself. Introduced in: SQL → Level 5 → Challenge 213
`CURRENT_TIMESTAMP`	SQL Server	Returns the current date and time.
`DATEADD`	SQL Server / MS Access	Adds a time/date interval to a date and returns the resulting date.
`DATEDIFF`	SQL Server / MS Access	Returns the difference between two dates, measured in a given unit. Introduced in: SQL → Level 5 → Challenge 223
`DATEFROMPARTS`	SQL Server	Builds a date from separate year, month, and day values.
`DATENAME`	SQL Server	Returns a specified part of a date as a readable string (e.g. month name).
`DATEPART`	SQL Server / MS Access	Returns a specified part of a date as an integer.
`DAY`	SQL Server / MS Access	Returns the day of the month for a given date. Introduced in: SQL → Level 2 → Challenge 90
`GETDATE`	SQL Server	Returns the current database system date and time.
`GETUTCDATE`	SQL Server	Returns the current database system date and time in UTC.
`ISDATE`	SQL Server	Checks whether an expression is a valid date and returns 1 or 0.
`MONTH`	SQL Server / MS Access	Returns the month (1–12) of a given date. Introduced in: SQL → Level 2 → Challenge 90
`SYSDATETIME`	SQL Server	Returns the date and time of the SQL Server, with higher precision than GETDATE.
`YEAR`	SQL Server	Returns the year of a given date. Introduced in: SQL → Level 2 → Challenge 90
`CONVERT`	SQL Server	Converts a value from one data type into another, with extra formatting style options.
`CURRENT_USER`	SQL Server	Returns the name of the current database user.
`IIF`	SQL Server	Returns one value if a condition is true, and another if it's false — an inline shortcut for CASE. Introduced in: SQL → Level 4 → Challenge 183
`ISNULL`	SQL Server	Returns a fallback value when an expression is NULL, otherwise returns the expression itself.
`ISNUMERIC`	SQL Server	Checks whether an expression evaluates to a valid numeric value.
`SESSION_USER`	SQL Server	Returns the name of the current database user (alias for CURRENT_USER).
`SESSIONPROPERTY`	SQL Server	Returns the current setting of a specified session option.
`SYSTEM_USER`	SQL Server	Returns the login name of the current user.
`USER_NAME`	SQL Server	Returns a database username based on its user ID.
`Asc`	MS Access	Returns the ASCII numeric code of a specific character. Introduced in: SQL → Level 1 → Challenge 27
`Chr`	MS Access	Returns the character that corresponds to a given ASCII code.
`Concat with &`	MS Access	Uses the & operator between strings to join them together. Introduced in: SQL → Level 2 → Challenge 85
`CurDir`	MS Access	Returns the full path of a specified drive's current directory.
`InStr`	MS Access	Returns the position of the first occurrence of a string within another string. Introduced in: SQL → Level 3 → Challenge 121
`InstrRev`	MS Access	Returns the position of the first occurrence of a string within another, searching from the end.
`LCase`	MS Access	Converts a string to lowercase.
`Replace`	MS Access	Replaces a substring within a string with another substring, up to a specified number of times. Introduced in: SQL → Level 3 → Challenge 123
`Split`	MS Access	Splits a string into an array of substrings using a delimiter.
`StrComp`	MS Access	Compares two strings and returns a value indicating how they relate.
`StrConv`	MS Access	Converts a string's case or format (e.g. to proper case).
`StrReverse`	MS Access	Reverses the order of characters in a string.
`Trim`	MS Access	Removes both leading and trailing spaces from a string. Introduced in: SQL → Level 3 → Challenge 122
`UCase`	MS Access	Converts a string to uppercase.
`Atn`	MS Access	Returns the arc tangent of a number.
`Cos`	MS Access	Returns the cosine of an angle.
`Fix`	MS Access	Returns the integer part of a number, truncating without rounding. Introduced in: SQL → Level 1 → Challenge 5
`Format`	MS Access	Formats a numeric value according to a specified display format. Introduced in: SQL → Level 2 → Challenge 89
`Int`	MS Access	Returns the integer part of a number, rounding toward negative infinity.
`Randomize`	MS Access	Seeds the random number generator used by Rnd().
`Rnd`	MS Access	Returns a random number.
`Sgn`	MS Access	Returns whether a number is negative (-1), zero (0), or positive (1).
`Sqr`	MS Access	Returns the square root of a number.
`Val`	MS Access	Reads a string and returns the numeric value found at its start.
`Date`	MS Access	Returns the current system date. Introduced in: SQL → Level 2 → Challenge 89
`DateSerial`	MS Access	Builds a date from separate year, month, and day values.
`DateValue`	MS Access	Converts a string into a date value.
`Format`	MS Access	Formats a date value according to a specified display format. Introduced in: SQL → Level 2 → Challenge 89
`MonthName`	MS Access	Returns the name of the month for a given month number.
`Now`	MS Access	Returns the current date and time from the computer's system clock. Introduced in: SQL → Level 1 → Challenge 5
`Time`	MS Access	Returns the current system time. Introduced in: SQL → Level 1 → Challenge 2
`TimeSerial`	MS Access	Builds a time value from separate hour, minute, and second values.
`TimeValue`	MS Access	Converts a string into a time value.
`Weekday`	MS Access	Returns a numeric weekday index for a given date. Introduced in: SQL → Level 5 → Challenge 224
`WeekdayName`	MS Access	Returns the name of the weekday for a given weekday number.
`CurrentUser`	MS Access	Returns the name of the currently logged-in database user.
`Environ`	MS Access	Returns the value of a specified operating-system environment variable.
`IsDate`	MS Access	Checks whether an expression can be converted into a valid date.
`IsNull`	MS Access	Checks whether an expression holds Null (no data) and returns True or False.
`IsNumeric`	MS Access	Checks whether an expression evaluates to a valid number.