IS NULL
Tests whether a value is NULL. See also NULL Values in MariaDB.
SELECT 1 IS NULL, 0 IS NULL, NULL IS NULL; +-----------+-----------+--------------+ | 1 IS NULL | 0 IS NULL | NULL IS NULL | +-----------+-----------+--------------+ | 0 | 0 | 1 | +-----------+-----------+--------------+
Some ODBC
applications use the syntax auto_increment_field IS NOT NULL
to find the latest row that was inserted with an autogenerated key value. If your applications need this, you can set the sql_auto_is_null variable to 1.
SET @@sql_auto_is_null=1; CREATE TABLE t1 (auto_increment_column INT NOT NULL AUTO_INCREMENT PRIMARY KEY); INSERT INTO t1 VALUES (NULL); SELECT * FROM t1 WHERE auto_increment_column IS NULL; +-----------------------+ | auto_increment_column | +-----------------------+ | 1 | +-----------------------+
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https://mariadb.com/kb/en/is-null/