SELECT
A.CODE,
B.NOTE,
C.NUMBER
FROM (A
LEFT JOIN B
ON A.CODE = B.CODE
LEFT JOIN C
ON A.CODE = C.NUMBER
)
WHERE C.ID = B.ID
Need to show some results combined from 3 tables, but my results show all data from table B reported also if the data isn't real from table C.
需要显示结合了3个表的一些结果，但是如果数据不是来自表C的，我的结果也显示了表B报告的所有数据。
Table A.code
1
2
3
Table B.code
1
2
3
Table B.note
pippo
paperino
pluto
Table C.number
1
Ideally there should be one result showing
理想情况下应该有一个结果显示
1 1 pippo
but in results it is shown:
但结果显示:
1 1 pippo
1 1 paperino
1 1 pluto
How can I get the real data?
我怎样才能得到真实的数据?
3 个解决方案
#1
3
SELECT
A.CODE,
B.NOTE,
C.NUMBER
FROM A
INNER JOIN B ON A.CODE = B.CODE
INNER JOIN C ON A.CODE = C.NUMBER
no need for WHERE cluse
不需要在哪里开玩笑
#2
1
You need INNER JOIN
你需要内连接
SELECT
A.CODE,
B.NOTE,
C.NUMBER
FROM C
INNER JOIN B on C.Number=B.Code
INNER JOIN A on B.Code=A.Code
#3
0
LEFT JOIN will take all results from the table mentioned on the left side. Try JOIN instead which is an INNER JOIN afaik
左连接将从左侧的表中获取所有结果。试试JOIN，它是一个内部连接
#1
3
SELECT
A.CODE,
B.NOTE,
C.NUMBER
FROM A
INNER JOIN B ON A.CODE = B.CODE
INNER JOIN C ON A.CODE = C.NUMBER
no need for WHERE cluse
不需要在哪里开玩笑
#2
1
You need INNER JOIN
你需要内连接
SELECT
A.CODE,
B.NOTE,
C.NUMBER
FROM C
INNER JOIN B on C.Number=B.Code
INNER JOIN A on B.Code=A.Code
#3
0
LEFT JOIN will take all results from the table mentioned on the left side. Try JOIN instead which is an INNER JOIN afaik
左连接将从左侧的表中获取所有结果。试试JOIN，它是一个内部连接