riyan哥SQL抬星

//

原来表：
id    name        con（留言内容）    points（3积分/条）
1     aa               加油                               3
2     qq               踩踩                               3
3     aa              支持哟                            3
4     cc               漂亮                                3
5     qq              加油                                3
如何合并成：
id    name    con（留言内容）  points
1     aa           加油|支持哟              6
2     qq           踩踩|加油                 6 
3     cc            漂亮                         3
//SQL"

'UPDATE `myblog` LEFT JOIN (SELECT `id`,`name`,GROUP_CONCAT(`con` SEPARATOR '|') AS `con`,SUM(`points`) AS `points` FROM `myblog` GROUP BY `name`) AS `tmp` USING(`id`) SET `myblog`.`name`=`tmp`.`name`,`myblog`.`con`=`tmp`.`con`,`myblog`.`points`=`tmp`.`points`';

 

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//避免重复插入

$sql = "INSERT INTO `table`(`a`,`b`) SELECT '$a', '$b' FROM dual WHERE NOT EXISTS (SELECT `a` FROM `table` WHERE `a`='$a' AND `b`='$b')";