Oracle Merge into使用小节（一）

Merge into 命令在Mybatis中如何使用

Merge into同一张表

模板

merge into 目标表 a

using 源表 b

on(a.条件字段1=b.条件字段1……)  

when matched then update set a.更新字段=b.字段

when  not macthed then insert into a(字段1,字段2……)values(值1,值2……)

源表b中查出的结果表示本次结果可以更改的结果集数量

on（条件）中的结果是匹配原则

实现

merge into Table aUSING (select count(1) as cnt from Tablewhere ID = #{id, jdbcType=TIMESTAMP}and CHANNEL_ID = #{channelId, jdbcType=INTEGER}) bon (b.cnt>0and a.ID= #{id, jdbcType=TIMESTAMP}and a.CHANNEL_ID = #{channelId, jdbcType=INTEGER})when MATCHED thenupdate set a.COUNT = a.COUNT + 1when not MATCHED theninsert (<if test="id != null">    a.ID,</if><if test="channelId != null">    a.CHANNEL_ID,</if><if test="count != null">    a.COUNT</if>)values(<if test="id != null">    #{id,jdbcType=VARCHAR},</if><if test="channelId != null">    #{channelId,jdbcType=INTEGER},</if><if test="count != null">    #{count,jdbcType=INTEGER},</if>)