Mybatis 标签

where 标签

用于处理select语句and等问题

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<select id="version" parameterType="long" resultType="int">
	SELECT column1, column2, columnN FROM table_name;
	<where>
	  	<if test="condition">
	  		 column1=#{value1}
	  	</if>
  	</where>
  </select>

set标签

用于处理update逗号，逗号等问题，与where类似

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<update id="update" parameterType="UserAlias">
    UPDATE table_name
    <set>
        <if test="condition">
	        column1 = #{value1}, column2 = #{value2}
	  	</if>
    </set>
</update>

##sql标签
sql标签与select等标签同级，相当于常量定义

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<sql id="select_content">column1, column2, columnN</sql>
<select id="version" parameterType="long" resultType="int">
	SELECT <include refid="select_content"></include> FROM table_name;
</select>

##trim标签
灵活的代替set或者where

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<trim prefix="set" suffixOverrides=","></trim>
<trim prefix="where" prefixOverrides="and"></trim>

##choose标签
可以当做if…else，也可以视为switch

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<choose>
	 <when test=""></when>
	 <when test=""></when>
	 <when test=""></when>
	 <otherwise></otherwise>
 </choose>

##collection与association标签
collection用来展示联合查询时子表内容的
association用来展示联合查询主表内容的

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<collection property="javaBean的主表名" resultMap="Namespace.ResultMap的id"/>
<association property="javaBean的子表名" resultMap="Namespace.ResultMap的id></association>

##标签总结
all lable