在mybatis 采用mapping文件 中的 oracle分页 SQL 配置在一个公用mapping中供后面引入使用

Posted 2020-11-11 jkyxs

1.在mybatis的公共mapping中添加下面设置

三层嵌套方式和用 row_number的方式都能到达效果，但是性能优劣众说纷纭我没亲自测试过。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="common.mapping.CommonMapper">

    <!-- ①采用rownum关键字(三层嵌套)有人说这个比下面更好 -->
    <sql id="Oracle_Pagination_Head">
        <if test="pageIndex !=null and pageSize !=null">
            <![CDATA[select y.* from(select z.*,rownum as oracleStart from (]]>
        </if>
    </sql>

    <sql id="Oracle_Pagination_Tail">
        <if test="pageIndex != null and pageSize != null">
            <![CDATA[ ) z where rownum <= (#{pageIndex}+1) * #{pageSize} ) y where y.oracleStart > #{pageIndex} * #{pageSize} ]]>
        </if>
    </sql>


    <!-- ②采用row_number解析函数进行分页(效率更高) -->
    <!-- SELECT xx.* FROM( SELECT t.*,row_number() over(ORDER BY o_id)AS num 
        FROM t_order t )xx WHERE num BETWEEN 5 AND 15 -->

    <sql id="Oracle_PageRowNuber_Head">
        <if test="pageIndex !=null and pageSize !=null">
            <![CDATA[SELECT xx.* FROM( SELECT t.*,row_number() over(ORDER BY order_no)AS num FROM (]]>
        </if>
    </sql>

    <sql id="Oracle_PageRowNuber_Tail">
        <if test="pageIndex != null and pageSize != null">
            <![CDATA[ )t ) xx WHERE num BETWEEN #{pageIndex} * #{pageSize}  AND （#{pageIndex}+1）* {pageSize}]]>
        </if>
    </sql>

</mapper>

 2. 后面直接引用

 

<select id="getListPageData" parameterType="java.util.HashMap"
        resultType="common.model.Row">
        <include
            refid="common.mapping.CommonMapper.Oracle_Pagination_Head" />
        select .........
　　　　 <include　　
            refid="common.mapping.CommonMapper.Oracle_Pagination_Tail" />
</select>