sql標籤:抽取可重用的sql片段,方便後面引用;
- sql抽取:經常將要查詢的列名,或者插入用的例名抽取出來方便引用;
- include標籤用來引用已經抽取出來的sql;
- include還可以自定義一些 property, sql標籤內部就可以使自定義的屬性;
<sql id="Base_Column_List"> id, name,sex,${someCol} </sql> <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap"> select <include refid="Base_Column_List"> <property name="someCol" value="age"/> </include> from user where id = #{id,jdbcType=INTEGER} </select>
如此,即可在selectByPrimaryKey方法得到語句:
select id, name,sex,age from user where id = #{id,jdbcType=INTEGER}