1.mysql中or語法的使用，在mysql語法中or使用注意點。?
??$sql?=?'SELECT? ????????????????*? ????????????FROM? ????????????????`vvt_spread_doubleegg_exchange_award`?AS?p ????????????WHERE ????????????????p.`act_type`?=?4?or?p.`act_type`?=?5 ????????????AND ????????????????p.`user_id`?=?'?.$user_id ????????????;
sql中的or語法一般用于多個條件的查詢，上面的語法查詢的相當于：兩個sql查詢出來的數據集合。
<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` = ' .$user_id</span>;</span></span>
2.? 要想查詢act_type = 4? and user_id = 11123 或者等于 p.`act_type` = 5 and user_id = 11123的數據集合 or兩邊的條件一定要加（）。
??$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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