MyBatis的 mapper.xml里面foreach标签里面的属性separator写逗号还是or

属性separator 为逗号

• 前段传过来的snapshotIds参数是list集合，类型为Integer或Long

select * from student_snapshot ss where 1=1
<if test="snapshotIds != null">
    and ss.id in
    <foreach collection="snapshotIds" item="item" open="(" close=")" separator=",">
             #{item}
    </foreach>
</if>

最后渲染为sql语句为

and ss.id in (1,2,3)

• 前段传过来的snapshotView参数是list集合，类型为实体类对象

public class snapshotView {

    private String snapshotIds = null;
    private String gradIds = null;
    private String classIds = null;
}

查询：

select * from student_snapshot ss where 1=1
<if test="snapshotView.snapshotIds != null">
    and ss.id in ( ${snapshotView.snapshotIds} )
</if>
<if test="snapshotView.snapshotIds == null">
    and ss.id in ( '' )
</if>

属性separator 为or

• 前段传过来的snapshotIds参数是list集合，类型为Integer或Long

select * from student_snapshot ss where 1=1
<if test="snapshotIds != null">
    and 
    <foreach collection="snapshotIds" item="item" open="(" close=")" separator=",">
          ss.id  =  #{item}
    </foreach>
</if>

最后渲染为sql语句为

and ( ss.id = 1 or ss.id = 2 or ss.id = 3)

• 前段传过来的userId参数，查询实体类集合对象（什么方法查的无所谓）

List<SysDeptEntity> deptEntityList = currencyFeign.getDeptByUserId(userId);

SysDeptEntity：

public class SysDeptEntity {

    private Long oid = null;
    private String deptCode = null;
    .....
}

查询：

select * from student_snapshot ss where 1=1
<if test="deptEntityList != null and deptEntityList.size() > 0">
        and
<foreach collection="deptEntityList" item="item" open="(" close=")" separator="or">
        ss.dept_code like concat(#{item.deptCode},'%')
</foreach>
</if>
<if test="deptEntityList == null or deptEntityList.size() == 0">
      and ss.dept_coid = null
</if>