MyBatis 动态SQL标签汇总

if 标签

<select id=getEmpByCondition resultType=com.xy.mybatis.dynamic.pojo.Emp>
    select * from emp
    where 1 = 1
    <if test=name != '' and name != null>
        and name = #{name}
    </if>
    <if test=age != '' and age != null>
        and age = #{age}
    </if>
</select>

where 标签

<select id=getEmpByCondition resultType=com.xy.mybatis.dynamic.pojo.Emp>
    select * from emp
    <where>
        <if test=name != '' and name != null>
            name = #{name}
        </if>
        <if test=age != '' and age != null>
            and age = #{age}
        </if>
    </where>
</select>

trim 标签

<select id=getEmpByCondition resultType=com.xy.mybatis.dynamic.pojo.Emp>
    select * from emp
    <trim prefix=where suffixOverrides=and prefixOverrides=and suffix=order by id desc>
        <if test=name != '' and name != null>
            name = #{name}
        </if>
        <if test=age != '' and age != null>
            and age = #{age}
        </if>
    </trim>
</select>

choose、when、otherwise 标签

<select id=getEmpByChoose resultType=com.xy.mybatis.dynamic.pojo.Emp>
    select * from emp
    <where>
        <choose>
            <when test=name != '' and name != null and age != '' and age != null>
                name = #{name} and age = #{age}
            </when>
            <when test=age != '' and age != null>
                age = #{age}
            </when>
            <when test=name != '' and name != null>
                name = #{name}
            </when>
            <otherwise>
                1 = 1
            </otherwise>
        </choose>
    </where>
</select>

foreach 标签

<select id=getEmpByIds resultType=com.xy.mybatis.dynamic.pojo.Emp>
    select * from emp
    <foreach collection=ids item=id open=where id in ( close=) separator=,>
        #{id}
    </foreach>
</select>

sql、include 标签

<sql id=base>
    select id, name, age
    from emp
</sql>

<select id=getEmpByIds resultType=com.xy.mybatis.dynamic.pojo.Emp>
    <include refid=base/>
    <foreach collection=ids item=id open=where id in ( close=) separator=,>
        #{id}
    </foreach>
</select>