MySQL Tutorial/String Functions/FIELD
FIELD(str,str1,str2,str3,...): Returns the index (position) of str in the str1, str2, str3, ... list
Returns 0 if str is not found.
If str is NULL, the return value is 0.
FIELD() is the complement of ELT().
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mysql> mysql> SELECT FIELD("A", "B", "A", "V", "D", "W"); +-------------------------------------+ | FIELD("A", "B", "A", "V", "D", "W") | +-------------------------------------+ | 2 | +-------------------------------------+ 1 row in set (0.00 sec) mysql> mysql> mysql> SELECT FIELD("Z", "A", "B", "C", "D", "E"); +-------------------------------------+ | FIELD("Z", "A", "B", "C", "D", "E") | +-------------------------------------+ | 0 | +-------------------------------------+ 1 row in set (0.02 sec) mysql></source>