SQL Functions
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Revision as of 23:28, 11 November 2011 by imported>Aeric (→Date and Time Functions)
These functions can be used in your SQL statements.
- Legend
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- [ x ] - Optional (one or none)
- [, x ... ] - Optional additional values, in a comma-separated list
- x | y - Choose one. Curly braces are added when needed: { x | y } ...
- CAPITALIZED - SQL Keyword (case insensitive)
- italicized - Value you supply. (Table names and column names are case-sensitive)
Logical Functions
IF(expr1,expr2,expr3) If expr1 is not zero and not null, return expr2. Otherwise, return expr3. IFNULL(expr1,expr2) If expr1 is not NULL, return expr1; Otherwise, return expr2.
- Learn more: MySQL Control Flow Functions
String Functions
CONCAT(str1,str2,...) Concatenates the strings. Returns the result. LENGTH(str) Returns the length of the string, in bytes. (A mult-byte character counts as multiple bytes.)
- Learn more: MySQL String Functions
Mathematical Functions
ROUND(x) Round x up or down to the nearest integer value. ROUND(x, d) Round xto d decimal places.
- Learn more: MySQL Mathematical Functions
Date and Time Functions
DATE_ADD(date, INTERVAL expr unit)
DATE_SUB(date, INTERVAL expr unit)Add expr units to a time value (or subtract from it.
where: expr can be a negative number, and where:
unit Expression Type Expression Format MICROSECOND
SECOND
MINUTE
HOUR
DAY
WEEK
MONTH
QUARTER
YEARSNumber An integer specifying the number of units. SECOND_MICROSECOND String 'SECONDS.MICROSECONDS' MINUTE_MICROSECOND String 'MINUTES:SECONDS.MICROSECONDS' MINUTE_SECOND String 'MINUTES:SECONDS' HOUR_MICROSECOND String 'HOURS:MINUTES:SECONDS.MICROSECONDS' HOUR_SECOND String 'HOURS:MINUTES:SECONDS' HOUR_MINUTE String 'HOURS:MINUTES' DAY_MICROSECOND String 'DAYS HOURS:MINUTES:SECONDS.MICROSECONDS' DAY_SECOND String 'DAYS HOURS:MINUTES:SECONDS' DAY_MINUTE String 'DAYS HOURS:MINUTES' DAY_HOUR String 'DAYS HOURS' YEAR_MONTH String 'YEARS-MONTHS'
DATEDIFF CURDATE NOW CURTIME DATE_FORMAT DATE DAYOFMONTH DAYNAME DAYOFWEEK DAYOFYEAR EXTRACT FROM_UNIXTIME HOUR LAST_DAY MINUTE MONTH MONTHNAME SEC_TO_TIME SECOND STR_TO_DATE SUBTIME TIME_TO_SEC TIME TIMEDIFF TO_DAYS UNIX_TIMESTAMP YEAR
- Learn more: MySQL Date and Time Functions
Aggregate Functions
SUM(expr)
SUM(DISTINCT expr)Returns the sum of the values in the expression, or of the distinct values in the expression. Returns NULL if the expression has no values. AVG(expr)
AVG(DISTINCT expr)Returns the average of the values in the expression, or of the distinct values in the expression. Returns NULL if the expression has no values. COUNT(expr) Returns a count of the number of non-NULL values of expr in the rows retrieved by a SELECT statement Returns 0 if there were no matching rows. COUNT(*) Returns a count of rows, whether or not they contain NULL values. COUNT(DISTINCT
expr [, expr ...])Returns a count of rows with different non-NULL expr values. MAX(expr)
MAX(DISTINCT expr)Returns the maximum of the values in the expression, or of the distinct values in the expression. Returns NULL if the expression has no values. MIN(expr)
MIN(DISTINCT expr)Returns the maximum of the values in the expression, or of the distinct values in the expression. Returns NULL if the expression has no values. STD(expr) Returns the standard deviation of expr. VARIANCE(expr) Returns the standard variance of expr.
- Learn more: MySQL Aggregate Functions