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  • MySQL 函数

    一、case 【列名称】 when【条件】 then 【返回值】... else 【返回值】end

    1、简单单一条件

    SELECT
    	CASE o.operate_status
    	  WHEN '1' THEN '暂停'
    	  WHEN '2' THEN '启用'
    	  WHEN '3' THEN '失效'
    	  ELSE '其他' END AS operate_status,
    	o.change_reason,
    	o.creator_name,
    	DATE_FORMAT(o.operate_time, '%Y-%m-%d %H:%i') AS operate_time
    FROM [tablName] AS o
    WHERE o.operate_status in ('1', '2', '3', '4', '5')  

    查询效果:

    2、多个条件

    SELECT
    	CASE o.operate_status
    	  WHEN '1' OR '2' THEN '编制'
    	  WHEN '3' OR '4' THEN '编制'
    	  WHEN '5' THEN '暂停'
    	  WHEN '6' THEN '启用'
    	  WHEN '7' THEN '失效'
    	  ELSE '其他' END AS operate_status,
    	CASE o.operate_status
    	  WHEN '1' THEN '暂存信息'
    	  WHEN '2' THEN '提交'
    	  WHEN '3' THEN '审核通过'
    	  WHEN '4' THEN '审核不通过'
    	  WHEN '5' THEN '暂停'
    	  WHEN '6' THEN '启用'
    	  WHEN '7' THEN '失效'
    	  ELSE '其他' END AS operate_result,
    	o.change_reason,
    	o.creator_name,
    	DATE_FORMAT(o.operate_time, '%Y-%m-%d %H:%i') AS operate_time
    FROM [tableName] AS o
    WHERE o.operate_status in ('1', '2', '3', '4', '5')
    

    查询效果如下: 

    二、case [ when 【条件】then【返回值】... else 【返回值】end ]

    SELECT 
    	CASE 
    	  WHEN o.operate_status = '1' OR o.operate_status = '2' THEN '编制'
    	  WHEN o.operate_status = '3' OR o.operate_status = '4' THEN '编制'
    	  WHEN o.operate_status = '5' THEN '暂停'
    	  WHEN o.operate_status = '6' THEN '启用'
    	  WHEN o.operate_status = '7' THEN '失效'
    	  ELSE '其他' END AS operate_status,
    	o.change_reason,
    	o.creator_name,
    	DATE_FORMAT(o.operate_time, '%Y-%m-%d %H:%i') AS operate_time
    FROM [tableName] AS o
    WHERE o.operate_status in ('1', '2', '3', '4', '5');

    查询效果如下:

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  • 原文地址:https://www.cnblogs.com/yuchuan/p/mysql_case_when.html
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