sql - SQL 查询所需的建议

Question

是否可以使用提供 SQL 查询的帮助来提取最大数量“columnb”值为“Active”的“columna”值。意味着在 columnb 中有一个值 "Active" ，我想拉出具有最大值 Active n columnb 的 columna 值。

我正在寻找输出为 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

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

小提琴

Answer 2

您请求的结果将通过以下方式产生：

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

Answer 3

RDMBS-es 之间的语法略有不同，但逻辑仍然存在。过滤您的行，按它们columnb分组columna，按顺序排列count(*)并选择前 1

SQL 服务器：

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

SQLFiddle 演示

MySQL：

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

SQLFiddle 演示

Answer 4

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