Question

可以使用一些提供SQL查询的帮助来提取“columna”值，其中最大数字“columnb”值为“Active”。在columnb中有一个值为“Active”的值，我想拉出columna值，该值具有最大值Active n columnb。

我看输出为columna = M1和Count = 4

columna     columnb
M1          Active
M1          Active
M1          Active
M1          Active
M2          failed
M2          failed
M2          failed
M3          pending
M3          pending
M3          pending

Answer 1

您要求的结果将由以下方式生成：

SELECT columna,COUNT(*)
FROM Table
WHERE columnb = 'Active'
GROUP BY columna

Answer 2

SELECT top 1 columna,COUNT(*) as cnt
FROM Table1
WHERE columnb = 'Active'
GROUP BY columna
order by cnt desc

<强> FIDDLE

Answer 3

SELECT columna,count(*) FROM TABLE_NAME where columnb = "Active" GROUP BY columna

Answer 4

RDMBS-es之间的语法略有不同，但逻辑仍然存在。根据{{1}}过滤您的行，按columnb对其进行分组，在columna上订购并选择前1

SQL Server：

count(*)

SQLFiddle DEMO

MySQL的：

SELECT TOP 1 columna, COUNT(*) AS Count
FROM YourTable
WHERE columnb = 'Active'
GROUP BY columna
ORDER BY COUNT(*) DESC

SQLFiddle DEMO

SQL查询所需的建议

4 个答案: