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数据库排序与索引优化

最新推荐文章于 2022-08-25 11:04:41 发布

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这段代码用于生成SQL查询中的排序语句，根据资源列的索引类型决定升序或降序排列。当处理第一条数据时，会依据索引类型进行asc或desc排序，对于后续数据则作为额外的排序条件。此段代码对于数据库查询性能优化具有重要意义。

<#list sortResourceTableColumns as column>
<#if column_index = 0>//第一条数据
		  <#if ((column.resourcecolumnIndexType??) && column.resourcecolumnIndexType == 1)>
		    order by ${column.resourcecolumnCode?replace("([a-z])([A-Z]+)","$1_$2","r")?lower_case} asc
		      <#elseif ((column.resourcecolumnIndexType??) && column.resourcecolumnIndexType == 2)>
		    order by ${column.resourcecolumnCode?replace("([a-z])([A-Z]+)","$1_$2","r")?lower_case} desc
		 </#if>
		<#else>
		  <#if ((column.resourcecolumnIndexType??) && column.resourcecolumnIndexType == 1)>
		    ,${column.resourcecolumnCode?replace("([a-z])([A-Z]+)","$1_$2","r")?lower_case} asc
		  <#elseif ((column.resourcecolumnIndexType??) && column.resourcecolumnIndexType == 2)>
		    ,${column.resourcecolumnCode?replace("([a-z])([A-Z]+)","$1_$2","r")?lower_case} desc
		  </#if>
		</#if>
		</#list>