NULLIF() - NULL on Equal Values

Q

How to generate NULL with equal values using the NULLIF() function?

✍: FYIcenter.com

A

NULLIF(val1, val2) is a MySQL built-in function that returns NULL if the first argument equals the second, the first argument otherwise. For example:

SELECT NULLIF('yes', 'yes'), NULLIF('yes', 'no');
  -- +----------------------+---------------------+
  -- | NULLIF('yes', 'yes') | NULLIF('yes', 'no') |
  -- +----------------------+---------------------+
  -- | NULL                 | yes                 |
  -- +----------------------+---------------------+

Reference information of the NULLIF() function:

NULLIF(val1, val2): val
  Returns NULL if the first argument equals the second, 
  the first argument otherwise.

Arguments, return value and availability:
  val1, val2: Required. The values to be selected from.
  val: Return value. NULL if val1=val2, val1 otherwise.
  Available since MySQL 4.0.

⇒ RELEASE_ALL_LOCKS() - Release All Locks

⇐ NAME_CONST() - PS Thread ID of Given Connect

⇑ MySQL Functions for Miscellaneous Purposes

⇑⇑ MySQL Function References

2023-12-19, 1476🔥, 0💬

IS_IPV6() - Detecting IPv6 Address
How to detect an IPv4 Address using the IS_IPV6() function? IS_IPV6(ip) is a MySQL built-in function that returns 1 if the given value is a valid IPv6 address, 0 otherwise. For example: SELECT IS_IPV4('10.0.5.9'), IS_IPV4('10.0.5.256'); -- +---------------------+------- ----------------+-- | IS_IPV4... 2026-01-24, 3954🔥, 0💬

CHARSET() - Detecting Character Set Name
How to detect the character set name associated to a given character string using the CHARSET() function? CHARSET(str) is a MySQL built-in function that returns the character set name associated to a given character string. A character set name refers to a set of rules to encode a set of characters ... 2025-10-24, 3518🔥, 0💬

UPDATEXML() - Updating Child Element in XML
How to update a child element in an XML document at a given location using the UPDATEXML() function? UPDATEXML(xml, path, subxml) is a MySQL built-in function that updates a child element in an XML document at a given location. For example: SET @xml = ' X Y '; SELECT UPDATEXML(@xml, '/a', ' Z '); +-... 2026-01-24, 3438🔥, 0💬

IS_IPV4() - Detecting IPv4 Address
How to detect an IPv4 Address using the IS_IPV4() function? IS_IPV4(ip) is a MySQL built-in function that returns 1 if the given value is a valid IPv4 address, 0 otherwise. For example: SELECT IS_IPV4('10.0.5.9'), IS_IPV4('10.0.5.256'); -- +---------------------+------- ----------------+-- | IS_IPV4... 2026-02-02, 3274🔥, 0💬

IS_IPV4_COMPAT() - IPv4-Compatible IPv6 Address
How to detect an IPv6 Address that is IPv4 compatible using the IS_IPV4_COMPAT() function? IS_IPV4_COMPAT(ip) is a MySQL built-in function that returns 1 if the given IPv6 address is IPv4-compatible, 0 otherwise. The IPv6 address must be given in number format. An IPv4-compatible IPv6 address has 12... 2026-02-02, 2597🔥, 0💬

VALUES() - Column Value for "ON DUPLICATE KEY UPDATE"
How to obtain the inserting value of given column in the "ON DUPLICATE KEY UPDATE" clause using the VALUES() function? VALUES(col) is a MySQL built-in function that returns the inserting value of a given column and use it in the "ON DUPLICATE KEY UPDATE" clause. For example: CREATE TABLE MyTable (id... 2025-10-24, 2522🔥, 0💬

SLEEP() - Holding Statement Execution
How to hold the statement execution for some time using the SLEEP() function? SLEEP(sec) is a MySQL built-in function that holds the execution of the current statement for sec seconds. For example: SELECT SYSDATE(), SLEEP(2), SYSDATE(); -- +---------------------+------- ---+---------------------+-- ... 2023-12-19, 1686🔥, 0💬

LEAST() - Finding the Least/Minimum Value
How to find the least (minimum) value of a given list of values using the LEAST() function? LEAST(val1, val2, ...) is a MySQL built-in function that returns the least (minimum) value of a given list of values. For example: SELECT LEAST(70, 89, 73, 99, 101, 110, 116, 101, 114); -- +------------------... 2023-12-19, 1647🔥, 0💬

NULLIF() - NULL on Equal Values
How to generate NULL with equal values using the NULLIF() function? NULLIF(val1, val2) is a MySQL built-in function that returns NULL if the first argument equals the second, the first argument otherwise. For example: SELECT NULLIF('yes', 'yes'), NULLIF('yes', 'no'); -- +----------------------+-----. .. 2023-12-19, 1477🔥, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.