随笔分类 -  SQL

摘要：在开发中往往要用到类似下面的二维统计：abtype15465type25454在SQL中使用CASE WHEN 语句可以很轻松的实现：SELECT SUM(CASE WHEN type='type1' THEN 1 ELSE 0 END) AS a,SUM(CASE WHEN type='type2' THEN 1 ELSE 0 END) AS bFROM Table1 阅读全文