如何計算sql中特定列的數量？

Question

我有一個名爲Employees的表，它有很多列，但我只想計算此表的某些特定列。

即 僱員：001

week1：40

week2：24

譯員更加：24

Week4：39

該僱員（001）具有2周下面32. 如何使用COUNT語句計算在這四周（列）內，多少星期（列）的值低於32？

Answer 1

像這樣的東西應該這樣做：

SELECT EmployeeID, 
    (CASE WHEN Week1 < 32 THEN 1 ELSE 0 END + 
    CASE WHEN Week2 < 32 THEN 1 ELSE 0 END + 
    CASE WHEN Week3 < 32 THEN 1 ELSE 0 END + 
    CASE WHEN Week4 < 32 THEN 1 ELSE 0 END) AS Count 
    FROM Employees ... 

Answer 2

SELECT COUNT(*) 
FROM [TableName]; 

可以使用

WHERE聲明SELECT ... FROM ...後指定，如員工與時間低於32

例如條件：

SELECT COUNT(*) 
FROM [TableName] 
WHERE `Hours`<'32'; 

使用AND運營商加入更多條件

SELECT COUNT(*) 
FROM [TableName] 
WHERE `Hours`<'32' AND `EmployeeName`='Todd'; 

Answer 3

SELECT 'MEMBERS(ACTIVE ACCOUNTS)' particular, ''value 
union all 
SELECT +' '+ member_type, 
    (SELECT active_students = (SELECT COUNT(member_type_id) FROM LM_MEMBER_MASTER 
    WHERE institute_code = 'GDAB' AND member_type_id = A.member_type_id AND status = 'Active')) 
FROM LM_MEMBER_TYPE_MASTER A WHERE institute_code = 'GDAB' 
union all 
Select ' Total' particular, COUNT(member_type_id) FROM LM_MEMBER_MASTER 
WHERE institute_code = 'GDAB' AND status = 'Active' 
union all 
SELECT 'MEMBERS(CLOSED ACCOUNTS)' particular, '' value 
union all 
SELECT +' '+member_type, 
    (SELECT active_students = (SELECT COUNT(member_type_id) FROM LM_MEMBER_MASTER 
    WHERE institute_code = 'GDAB' AND member_type_id = A.member_type_id AND status = 'Closed')) 
FROM LM_MEMBER_TYPE_MASTER A WHERE institute_code = 'GDAB' 
union all 
Select ' Total' particular, COUNT(member_type_id) FROM LM_MEMBER_MASTER 
WHERE institute_code = 'GDAB' AND status = 'Closed' 

在此代碼，我不想算「成員（有效帳戶）」和「會員（已關閉的帳戶）」 bcoz其頭條