Easy Transact SQL Question

I'm a novice with SQL Querying, and can't figure out an update command.
My SELECT statement is as follows:
SELECT * FROM table1, table2
WHERE table1.keyfield = table2.keyfield and table2.field is not null
How do I convert this to an update statement on a field in table1 while
maintaining the restriction based on the field in table2?
Thanks for the help!Cindy Mikeworth wrote:
> I'm a novice with SQL Querying, and can't figure out an update command.
> My SELECT statement is as follows:
> SELECT * FROM table1, table2
> WHERE table1.keyfield = table2.keyfield and table2.field is not null
> How do I convert this to an update statement on a field in table1 while
> maintaining the restriction based on the field in table2?
> Thanks for the help!
For example:
UPDATE table1
SET col1 = 1234
WHERE EXISTS
(SELECT *
FROM table2
WHERE table2.keycol = table1.keycol
AND table2.col IS NOT NULL) ;
David Portas, SQL Server MVP
Whenever possible please post enough code to reproduce your problem.
Including CREATE TABLE and INSERT statements usually helps.
State what version of SQL Server you are using and specify the content
of any error messages.
SQL Server Books Online:
http://msdn2.microsoft.com/library/ms130214(en-US,SQL.90).aspx
--|||First learn that rows are NOT anythign like records, nor are columns
anything like a field. it is VITAL to have the right mindset in SQL
SELECT *
FROM Table1, Table2
WHERE table1.keyfield = table2.keyfield
AND table2.field IS NOT NULL;
You don't do it at all!! One of the MANY differences between a field
and column is that a column can have constraints on it. An SQL
programmer woudl have done this in the DDL (do you know what DDL is? If
not, you are sooooo screwed).
Please post DDL, so that people do not have to guess what the keys,
constraints, Declarative Referential Integrity, data types, etc. in
your schema are. Sample data is also a good idea, along with clear
specifications. It is very hard to debug code when you do not let us
see it. Could you program from what you posted? HOW?!
If you have a key, in ANY table is BY DEFINITION NOT NULL, so your|||Cindy Mikeworth (CindyMikeworth@.newsgroups.nospam) writes:
> I'm a novice with SQL Querying, and can't figure out an update command.
> My SELECT statement is as follows:
> SELECT * FROM table1, table2
> WHERE table1.keyfield = table2.keyfield and table2.field is not null
> How do I convert this to an update statement on a field in table1 while
> maintaining the restriction based on the field in table2?
UPDATE table1
SET field = ...
FROM table1, table2
WHERE table1.keyfield = table2.keyfield
and table2.field is not null
This uses a non-standard extension of the UPDATE statement that is
proprietary to SQL Server and Sybase. As long as one is careful that
the join produces a unique value for the row to update, this is a very
practical method, not the least because it's so easy to transform a
SELECT into an UPDATE.
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pr...oads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodin...ions/books.mspx|||UPDATE t1
SET t1.column1 = t2.value
FROM table1 t1
INNER JOIN table2 t2
ON t1.keyfield = t2.keyfield
WHERE t2.field IS NOT NULL