加入兩個表格不起作用

表1數據：

Id org_id start_date end_date  month 
'1', '46', '2015-01-01', '2015-01-31', 'January' 
'2', '46', '2015-02-01', '2015-02-28', 'February' 
'3', '46', '2015-03-01', '2015-03-31', 'March' 
'4', '46', '2015-04-01', '2015-04-30', 'April' 
'5', '46', '2015-05-01', '2015-05-31', 'May' 
'6', '46', '2015-06-01', '2015-06-30', 'June' 
'7', '46', '2015-07-01', '2015-07-31', 'July' 
'8', '46', '2015-08-01', '2015-08-31', 'August' 
'9', '46', '2015-09-01', '2015-09-30', 'September' 
'10', '46', '2015-10-01', '2015-10-31', 'October' 
'11', '46', '2015-11-01', '2015-11-30', 'November' 
'12', '46', '2015-12-01', '2015-12-31', 'December'

表2數據：

Id org_id from_date emp_id 
'48', '46', '2015-06-09' 1 
'49', '46', '2015-06-09' 1 
'50', '46', '2015-06-01' 2 
'51', '46', '2015-05-20' 1 
'56', '46', '2015-07-07' 2

這是我的查詢：

select t1.month,count(t2.emp_id) as count 
from Table1 t1 
left outer join Table2 t2 on t2.from_date between t1.start_date and t1.end_date 
where t2.org_id=46 group by t1.month

輸出我得到的是：

month count 
'July', '1' 
'June', '3' 
'May', '1'

輸出我期待的是：

month count 
'January', '0' 
'February', '0' 
'March', '0' 
'April', '0' 
'May', '1' 
'June', '3' 
'July', '1' 
'August', '0' 
'September', '0' 
'October', '0' 
'November', '0' 
'December', '0'

我用左外連接。但左表中的所有記錄都沒有被抓取。

任何幫助！

來源

2015-06-17 0991

你必須把你的where statament的部分上CLASE：

select t1.month,count(t2.emp_id) as count 
from Table1 t1 
left outer join Table2 t2 on t2.from_date between t1.start_date and t1.end_date 
and t2.org_id=46 group by t1.month

如果你不這樣做，你有一個inner join

來源

2015-06-17 07:06:40 Jens

我不能按照我的預期結果訂購嗎？我用了t1.month的順序。但不工作。 – 0991

@ 0991你必須使用'按字段排序（t1.month，'January'，'February'，...）'等等。 – Jens

Thanks..work fine .. – 0991

試試這個..

SELECT t1.month,COUNT(t2.emp_id) AS COUNT 
    FROM Table1 t1 
    LEFT JOIN Table2 t2 ON t2.from_date BETWEEN t1.start_date AND t1.end_date 
    AND t2.org_id=46 GROUP BY t1.month

來源

2015-06-17 07:29:54

感謝您的答覆。 – 0991

加入兩個表格不起作用

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