动态SQL是MyBatis最强大的特性之一。用于实现动态SQL的主要元素如下：
1、where、if
2、choose、when、otherwise
3、set、trim
1、where、if
2、choose、when、otherwise
3、set、trim
4、foreach
| 1、where、if | <select id="getEmpByIf" resultType="Emp" parameterType="Emp"> select * from emp <where> <if test="job != null and job != ''"> and job = #{job} </if> </where> </select> |
| 2、choose、when、otherwise |
<select id="getEmpByChoose" resultType="Emp" parameterType="Emp"> select * from emp where 1 = 1 <choose> <when test="job != null"> and job = #{job} </when> <when test="deptno != null"> and deptno = #{deptno} </when> <otherwise> and mgr = #{mgr} </otherwise> </choose> </select> |
| 3、set、trim | |
| 4.1、foreach:参数数组 |  |
| 4.2、foreach:参数List |
整理自：https://blog.csdn.net/qq_32588349/article/details/51541871