SQL查詢所需的建議

Question

是否有人可以幫助提供SQL查詢，以便將具有最大數目「columnb」值的「columna」值拉出爲「Active」。在columnb中意味着有一個值「活動」，我想拉動最大值爲Active n columnb的columna值。

我期待輸出爲columna = M1和計數= 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

您請求將通過以下產生的結果：

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 

FIDDLE

Answer 3

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

Answer 4

RDMBS-es之間的語法略有不同，但邏輯依然存在。通過columna過濾您行基於columnb，它們分組，責令其在count(*)選擇頂部1

SQL服務器：

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

SQLFiddle DEMO

的MySQL：

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

SQLFiddle DEMO