查詢多個表對於特定日期範圍同時

Question

我有三個相同的表：

• gradbusdb.user
• gradedudb.user
• gradtheologydb.user

在各表中，我有email和submited_date在YYYY- MM-DD格式。我的最終目標是同時查詢所有三個表，但是當我在email和submited_date列的3個表之間執行UNION時，它會忽略我的WHERE條件並顯示所有結果。

我當前的查詢如下：

SELECT email, submited_date FROM gradbusdb.user 
UNION 
SELECT email, submited_date FROM gradedudb.user 
UNION 
SELECT email, submited_date FROM gradtheologydb.user 
WHERE submited_date BETWEEN '2016-02-01' AND '2016-02-29' 
ORDER BY submited_date ASC 

我不知道我做錯了這裏，但我需要我的查詢，顯示僅日期範圍內的結果。

Answer 1

您應該使用WHERE對於每個查詢到工會

SELECT email, submited_date FROM gradbusdb.user 
WHERE submited_date BETWEEN '2016-02-01' AND '2016-02-29' 
UNION 
SELECT email, submited_date FROM gradedudb.user 
WHERE submited_date BETWEEN '2016-02-01' AND '2016-02-29' 
UNION 
SELECT email, submited_date FROM gradtheologydb.user 
WHERE submited_date BETWEEN '2016-02-01' AND '2016-02-29' 

ORDER BY submited_date ASC