Regular Expressions • return_option : Which type of position to return. If this value is 0,  REGEXP_INSTR()  returns the position of the matched substring’s first character. If this value is 1,  REGEXP_INSTR()  returns the position following the matched substring. If omitted, the default is 0. • match_type : A string that specifies how to perform matching. The meaning is as described for REGEXP_LIKE() . For additional information about how matching occurs, see the description for  REGEXP_LIKE() . 2192 mysql>  SELECT REGEXP_INSTR(’dog cat dog’, ’dog’); +------------------------------------+ | REGEXP_INSTR(’dog cat dog’, ’dog’) | +------------------------------------+ | 1 | +------------------------------------+ mysql>  SELECT REGEXP_INSTR(’dog cat dog’, ’dog’, 2); +---------------------------------------+ | REGEXP_INSTR(’dog cat dog’, ’dog’, 2) | +---------------------------------------+ | 9 | +---------------------------------------+ mysql>  SELECT REGEXP_INSTR(’aa aaa aaaa’, ’a{2}’); +-------------------------------------+ | REGEXP_INSTR(’aa aaa aaaa’, ’a{2}’) | +-------------------------------------+ | 1 | +-------------------------------------+ mysql>  SELECT REGEXP_INSTR(’aa aaa aaaa’, ’a{4}’); +-------------------------------------+ | REGEXP_INSTR(’aa aaa aaaa’, ’a{4}’) | +-------------------------------------+ | 8 | +-------------------------------------+