构造一个SQL查询 [英] constructing a sql query

问题描述

嗨


我在使用某些sql时遇到了麻烦，不知道我的桌面设计是不是
不正确。


我有一张代表姓名表。


我有一张代表可以回答的问题表。

然后我有一个表，每个代表包含许多行，每行

显示代表已回答的问题。


所以例如，委托id 10已回答问题1和问题7，所以

会有两行


DelegateID QuestionID

10 1

10 7

等


我如何编写一个选择已回答问题1的代表的查询

和问题7？


我试过select delegateID where questionID = 1 AND questionID = 7，但

当然没有记录因为没有记录满足这两个问题

ID，所以归还了。


非常感谢任何帮助。

解决方案

questionID = 1 OR questionID = 7


Daveíà？è？àa：

嗨


我有一些sql的问题，不知道我的桌面设计是不是
不正确。


我有一个代表名称表。


我有一个代表可以回答的问题表。

然后我有一个表，其中包含每个代表的许多行，每个代表行

显示代表已回答哪个问题。


例如，delegate id 10已回答问题1和问题7，所以

会有两行


DelegateID QuestionID

10 1

10 7


等


如何编写一个选择已回答问题的代理的查询第1页

和问题7？


我试过select delegateID where questionID = 1 AND questionID = 7，但

当然没有记录被退回，因为没有记录满足这两个问题

ID。


任何帮助将不胜感激。

我试过了，但是如果他们已经完成

这个问题会给出一个委托ID，但我只想要获得代表ID，如果他们已经完成了两个问题。


谢谢


" que" < va ****** @ gmail.com写信息

新闻：11 ********************* @ 16g2000cwy。 googlegrou ps.com ...

questionID = 1或者questionID = 7


Daveíà？è？àa：

嗨


我遇到一些sql的麻烦，不知道我的桌面设计是不是
不正确。


我有一张代表姓名表。


我有一张代表可以回答的问题表。

然后我有一个表，其中包含每个代表的许多行，每行

显示代表已回答的问题。


所以例如，delegate id 10已回答问题1和问题7，所以

会有两行


DelegateID QuestionID

10 1

10 7

等


我如何编写一个选择已经回答的代表的查询疑问句

1

和问题7？


我试过select delegateID where questionID = 1 AND questionID = 7，但是

当然没有记录被退回，因为没有记录满足这两个问题

ID。


任何帮助将不胜感激。

Dave写道：

我已经尝试过了，但是如果他们已经完成

这个问题，那将会给出一个代表ID，但我只想获得代表ID，如果他们已经完成

已完成两个问题。


谢谢


" que" < va ****** @ gmail.com写信息

新闻：11 ********************* @ 16g2000cwy。 googlegrou ps.com ...

questionID = 1或者questionID = 7


Daveíà？è？àa：

嗨


我遇到一些sql的麻烦，不知道我的桌面设计是不是
不正确。


我有一张代表姓名表。


我有一张代表可以回答的问题表。

然后我有一个表，其中包含每个代表的许多行，每行

显示代表已回答的问题。


所以例如，delegate id 10已回答问题1和问题7，所以

会有两行


DelegateID QuestionID

10 1

10 7

等


我如何编写一个选择代表的查询已回答问题

1

和问题7？


我试过select delegateID where questionID = 1 AND questionID = 7，butof

当然没有记录被退回，因为没有记录满足这两个问题

ID。


任何帮助将不胜感激。

SELECT t1 .DelegateID`

FROM mytable t1

LEFT JOIN mytable t2 ON t1 .DelegateID` = t2 .DelegateID`

WHERE t1 .QuestionID` = 1

AND t2 .QuestionID` = 7

Hi

I''m having trouble with some sql and don''t know if my table design is
incorrect.

I have a table of delegate names.

I have a table of possible questions the delegate can answer.

I then have a table which contains many rows for each delegate, each row
showing which question the delegate has answered.

So for example, delegate id 10 has answered question 1 and question 7, so
there would be two rows

DelegateID QuestionID
10 1
10 7

etc.

How do i write a query that selects delegates that have answered question 1
AND question 7?

I tried "select delegateID where questionID=1 AND questionID=7, but of
course no records were returned since no records satisfied both question
IDs.

Any help would be greatly appreciated.

解决方案

questionID=1 OR questionID=7

Dave íà?è?àa:

Hi

I''m having trouble with some sql and don''t know if my table design is
incorrect.

I have a table of delegate names.

I have a table of possible questions the delegate can answer.

I then have a table which contains many rows for each delegate, each row
showing which question the delegate has answered.

So for example, delegate id 10 has answered question 1 and question 7, so
there would be two rows

DelegateID QuestionID
10 1
10 7

etc.

How do i write a query that selects delegates that have answered question1
AND question 7?

I tried "select delegateID where questionID=1 AND questionID=7, but of
course no records were returned since no records satisfied both question
IDs.

Any help would be greatly appreciated.

I have tried that, but that will give a delegate id if they have completed
either question, but i only want to get the delegate id if they have
completed BOTH questions.

Thanks

"que" <va******@gmail.comwrote in message
news:11*********************@16g2000cwy.googlegrou ps.com...
questionID=1 OR questionID=7

Dave íà?è?àa:

Hi

I''m having trouble with some sql and don''t know if my table design is
incorrect.

I have a table of delegate names.

I have a table of possible questions the delegate can answer.

I then have a table which contains many rows for each delegate, each row
showing which question the delegate has answered.

So for example, delegate id 10 has answered question 1 and question 7, so
there would be two rows

DelegateID QuestionID
10 1
10 7

etc.

How do i write a query that selects delegates that have answered question
1
AND question 7?

I tried "select delegateID where questionID=1 AND questionID=7, but of
course no records were returned since no records satisfied both question
IDs.

Any help would be greatly appreciated.

Dave wrote:

I have tried that, but that will give a delegate id if they have completed
either question, but i only want to get the delegate id if they have
completed BOTH questions.

Thanks

"que" <va******@gmail.comwrote in message
news:11*********************@16g2000cwy.googlegrou ps.com...
questionID=1 OR questionID=7

Dave íà?è?àa:

Hi

I''m having trouble with some sql and don''t know if my table design is
incorrect.

I have a table of delegate names.

I have a table of possible questions the delegate can answer.

I then have a table which contains many rows for each delegate, each row
showing which question the delegate has answered.

So for example, delegate id 10 has answered question 1 and question 7, so
there would be two rows

DelegateID QuestionID
10 1
10 7

etc.

How do i write a query that selects delegates that have answered question
1
AND question 7?

I tried "select delegateID where questionID=1 AND questionID=7, butof
course no records were returned since no records satisfied both question
IDs.

Any help would be greatly appreciated.

SELECT t1.`DelegateID`
FROM mytable t1
LEFT JOIN mytable t2 ON t1.`DelegateID` = t2.`DelegateID`
WHERE t1.`QuestionID` = 1
AND t2.`QuestionID` = 7

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