MySQL Functions
Quick MySQL function reference. Organised by purpose, with one-line summaries — read the MySQL docs for full signatures.
String
| Function | Does |
|---|---|
CONCAT(a, b, …) | Join strings. |
CONCAT_WS(sep, a, b) | Join with a separator. |
UPPER(s) / LOWER(s) | Case. |
SUBSTRING(s, pos, len) | Substring. |
LENGTH(s) / CHAR_LENGTH(s) | Bytes / characters. |
REPLACE(s, from, to) | Replace. |
TRIM(s) | Trim whitespace. |
LPAD / RPAD | Pad to length. |
Numeric
ABS, CEIL, FLOOR, ROUND(x, n), MOD(x, y), POWER, SQRT, RAND(), SIGN, TRUNCATE.
Date / time
| Function | Returns |
|---|---|
NOW() | Current datetime. |
CURDATE() / CURTIME() | Today / now-time only. |
DATE(x) | Strip the time part. |
DATE_ADD(x, INTERVAL 7 DAY) | Add an interval. |
DATEDIFF(a, b) | Days between. |
DATE_FORMAT(x, '%Y-%m') | Format to string. |
UNIX_TIMESTAMP(x) | Seconds since epoch. |
Aggregate & conditional
COUNT, SUM, AVG, MIN, MAX, GROUP_CONCAT, IFNULL(x, y), COALESCE(a, b, …), IF(cond, t, f), CASE … END.
JSON (MySQL 5.7+)
JSON_OBJECT('k', v), JSON_ARRAY(…), JSON_EXTRACT(j, '$.k') (shortcut j->'$.k'), JSON_UNQUOTE, JSON_SET, JSON_VALID.
Tip: The MySQL docs have a search bar — for any function not listed here, type
MYSQL_FUNCTION_NAME mysql docs in your favourite search engine and the official page is the first result.Example
Example
SELECT NOW(), CURDATE(),
UPPER('hi'), CONCAT('a','b'),
IFNULL(phone, 'n/a')
FROM customers;
Try it Yourself »
Exercise
MySQL function returning the current datetime.
SELECT
();
Three letters.
Discussion
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