功能

可定义需重复使用的SQL片段。在其他语句中使用include引入

示例

  • 可以传入变量

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    <sql id="tableColumns">
        ${table}.id, ${table}.username
    </sql>
    <select id="selectUser" resultType="User">
        select
            <include refid="tableColumns">
                <property name="table" value="user"/>
            </include>
        from user
        where username=#{username}
    </select>

  • 也可以嵌套引用

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    <sql id="sometable">
        ${prefix}Table
    </sql>
    <sql id="someinclude">
        from
        <include refid="${include_target}"/>
    </sql>
    <select id="select" resultType="map">
        select
            field1, field2, field3
        <include refid="someinclude">
            <property name="prefix" value="Some"/>
            <property name="include_target" value="sometable"/>
        </include>
    </select>