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Help with updating column in one table with values from table in another table.

Posted on 2013-12-17
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Last Modified: 2013-12-18
I have two tables (TableA and TableB).  I would like to update the values in TableA NEWCOLUMN to match the values in TableB OLDCOLUMN when ID is equal.  NEWCOLUMN and OLDCOLUMN are geometry columns.

TableA

ID  | NEWCOLUMN
0   |
1   |
2   |
3   |
4   |
5   |


TableB


ID  | OLDCOLUMN
------------------
1   | a
2   | b
3   | c
4   | d
5   | e
6   | f
7   | g
8   | h



I had used the following query in the past, but am now getting an error when I try to update.

UPDATE TableA
SET TableA.NEWCOLUMN = (SELECT TableB.OLDCOLUMN FROM TableB WHERE TableA.ID = TableB.ID)

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I get the following error:

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
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Question by:VAMS1
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2 Comments
 
LVL 66

Accepted Solution

by:
Jim Horn earned 500 total points
ID: 39724148
Give this a whirl..
UPDATE TableA
SET TableA.NEWCOLUMN = TableB.OLDCOLUMN
FROM TableA
   JOIN TableB ON TableA.ID = TableB.ID

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btw Nice job laying out your question.
0
 
LVL 66

Expert Comment

by:Jim Horn
ID: 39724167
>Subquery returned more than 1 value.
btw The reason for the error is whenever you have a 'SET column_name = (subquery)', when we're assigning the return set of a query to a scalar variable, the (subquery) can only return one value.

>SELECT TableB.OLDCOLUMN FROM TableB WHERE TableA.ID = TableB.ID
Which returned every ID where there was a match, hence the error.
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