Sql 在select语句中分组数据

我有大量的数据，需要在检索时分类到不同的组。每组都有不同的情况。我不想单独检索它们。我想知道使用一条sql语句每个组中的项数

例如，伪代码如下所示：

Select count(IssueID) as Issue1_Count if(condition1), 
count(IssueID) as Issue2_Count if(condition2),
count(IssueID) as Issue3_Count if(condition3)
From table1, table2, tabl3
where common_condition1 and common_Condition2;

SELECT 
       SUM(CASE WHEN condition1 THEN 1 ELSE 0 END) as Issue1_Count,
       SUM(CASE WHEN condition2 THEN 1 ELSE 0 END) as Issue2_Count,
       SUM(CASE WHEN condition3 THEN 1 ELSE 0 END) as Issue3_Count,
FROM 
       table1, table2, tabl3
WHERE 
       common_condition1 and common_Condition2;

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有人能帮我做一个Oralce查询吗…

Oracle的案例陈述应该对您有所帮助。看看这个：

虽然有一些限制，但我不是100%肯定你可以使用它们来做你在这里所做的事情。

这样说：

Select count(IssueID) as Issue1_Count if(condition1), 
count(IssueID) as Issue2_Count if(condition2),
count(IssueID) as Issue3_Count if(condition3)
From table1, table2, tabl3
where common_condition1 and common_Condition2;

SELECT 
       SUM(CASE WHEN condition1 THEN 1 ELSE 0 END) as Issue1_Count,
       SUM(CASE WHEN condition2 THEN 1 ELSE 0 END) as Issue2_Count,
       SUM(CASE WHEN condition3 THEN 1 ELSE 0 END) as Issue3_Count,
FROM 
       table1, table2, tabl3
WHERE 
       common_condition1 and common_Condition2;