合并前的數組a：array(size=3)0=>array(size=2)'id'=>string'113'(length=3)'email'=>string'[email protected]'(length=24)1=>array(size=2)'id'=>string'111'(length=3)'email'=>string'[email protected]'(length=24)2=>array(size=2)'id'=>string'109'(length=3)'email'=>string'[email protected]'(length=19)合并前的數組b：array(size=2)0=>array(size=2)'user_id'=>string'113'(length=2)'count'=>string'1'(length=1)1=>array(size=2)'user_id'=>string'109'(length=2)'count'=>string'8'(length=1)合并后的數組（合并條件，a的id==b的user_id時合并）：array(size=3)0=>array(size=3)'id'=>string'113'(length=3)'email'=>string'[email protected]'(length=24)'count'=>string'1'(length=1)1=>array(size=3)'id'=>string'111'(length=3)'email'=>string'[email protected]'(length=24)'count'=>string'0'(length=1)2=>array(size=3)'id'=>string'109'(length=3)'email'=>string'[email protected]'(length=19)'count'=>string'8'(length=1)