mybatis-dynamic sql

最新推荐文章于 2025-09-12 18:08:49 发布

转载最新推荐文章于 2025-09-12 18:08:49 发布 · 64 阅读

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原文链接：https://my.oschina.net/iioschina/blog/1858999

文章标签：

#java #python

本文介绍了使用MyBatis进行复杂条件查询的方法，包括if标签实现动态SQL、choose标签缩小查询范围、trim标签优化SQL语法、foreach处理集合参数以及bind标签预定义变量等技巧。

2019独角兽企业重金招聘Python工程师标准>>>

OGNL expressions

if 判断是否存在值

<select id="findActiveBlogLike" resultType="Blog"> SELECT * FROM BLOG WHERE state = ‘ACTIVE’ <if test="title != null"> AND title like #{title} </if> <if test="author != null and author.name != null"> AND author_name like #{author.name} </if> </select>

choose when otherwise . 缩小查询的范围

<select id="findActiveBlogLike" resultType="Blog"> SELECT * FROM BLOG WHERE state = ‘ACTIVE’ <choose> <when test="title != null"> AND title like #{title} </when> <when test="author != null and author.name != null"> AND author_name like #{author.name} </when> <otherwise> AND featured = 1 </otherwise> </choose> </select>

trim, where, set

foreach

<select id="selectPostIn" resultType="domain.blog.Post"> SELECT * FROM POST P WHERE ID in <foreach item="item" index="index" collection="list" open="(" separator="," close=")"> #{item} </foreach> </select>

bind

<select id="selectBlogsLike" resultType="Blog"> <bind name="pattern" value="'%' + _parameter.getTitle() + '%'" /> SELECT * FROM BLOG WHERE title LIKE #{pattern} </select>

转载于:https://my.oschina.net/iioschina/blog/1858999