将两个不同表中的两列插入SQL中的另一个表中

Question

I have been searching for a solution to my problem for quite a bit, but couldn't find anywhere. Here is my problem: I have two columns from two different tables and want to insert them into another table which is empty. I have tried to run this query but it doesn't work and I don't even know why:

SELECT a.column, c.column 
FROM FirstTable.column a, SecondTable.column c
left outer join ThirdTable.column b on a.column = b.column
left outer join ThirdTable.column b on c.column = b.column

After running this, I receive the following message:

Msg 4104, Level 16, State 1, Line 3
The multi-part identifier "a.column" could not be bound.
Msg 1011, Level 16, State 1, Line 1
The correlation name 'b' is specified multiple times in a FROM clause.

I would also like to add that a.column has 1143 rows, and c.column has 2057 rows. Both are PK for their respective tables.

Any help would be more than appreciated.

Answer 1

Try reframing your query as

SELECT a.column, c.column 
FROM Table a left outer join Table b on a.column = b.column 
left outer join Table c on c.column = b.column

Would have been better if you provided exact query, but the problem is most likely with the joins.

Answer 2

I used a set of temp table variables to display the concept, but it should be easily translated to actual tables.

DECLARE @tabl1 TABLE (col1 int DEFAULT 1)
    INSERT INTO @tabl1 VALUES (1)

DECLARE @tabl2 TABLE (col2 int DEFAULT 2)
    INSERT INTO @tabl2 VALUES (2)

DECLARE @tabl3 TABLE (col1 int, col2 int)

-- This should be what you need.

INSERT INTO @tabl3
SELECT a.col1
     , b.col2
FROM @tabl1 a, @tabl2 b

SELECT * FROM @tabl3

Answer 3

Unless you're doing a cartesian join, you've got a mixture of explicit and implicit syntax. I would pick one or the other (being partial to explicit syntax myself):

SELECT a.column, c.column 
FROM Table a
left outer join Table b on a.column = b.column
left outer join Table c on b.column = c.column

or whatever works for your structure.