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1.mysql中or语法的使用,在mysql语法中or使用注意点。
$sql = 'SELECT * FROM `vvt_spread_doubleegg_exchange_award` AS p WHERE p.`act_type` = 4 or p.`act_type` = 5 AND p.`user_id` = ' .$user_id ;
sql中的or语法一般用于多个条件的查询,上面的语法查询的相当于:两个sql查询出来的数据集合。
<span style="color: #000000"> $sql = 'SELECT * FROM `vvt_spread_doubleegg_exchange_award` AS p WHERE p.`act_type` = 4;<br/><span style="color: #000000">$sql = 'SELECT * FROM `vvt_spread_doubleegg_exchange_award` AS p WHERE <span style="color: #000000">p.`act_type` = 5 AND p.`user_id` = ' .$user_id</span>;</span></span>
2. 要想查询act_type = 4 and user_id = 11123 或者等于 p.`act_type` = 5 and user_id = 11123的数据集合 or两边的条件一定要加()。
$sql = 'SELECT * FROM `vvt_spread_doubleegg_exchange_award` AS p WHERE (p.`act_type` = 4 or p.`act_type` = 5) AND p.`user_id` = ' .$user_id ;
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