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18 Οκτ 2019 · The multi-table UPDATE syntax in MySQL is different from Microsoft SQL Server. You don't need to say which table(s) you're updating, that's implicit in your SET clause. UPDATE tableA a JOIN tableB b ON a.a_id = b.a_id JOIN tableC c ON b.b_id = c.b_id SET b.val = a.val+c.val WHERE a.val > 10 AND c.val > 10;
14 Δεκ 2014 · I have a user defined function: create function ut_FooFunc(@fooID bigint, @anotherParam tinyint) returns @tbl Table (Field1 int, Field2 varchar(100)) as. begin. -- blah blah. end. Now I want to join this on another table, like so: select f.ID, f.Desc, u.Field1, u.Field2.
This tutorial shows you how to perform cross-table updates by using the MySQL UPDATE JOIN statement with the INNER JOIN or LEFT JOIN clause.
To query data from related tables, you often use the join clauses, either inner join or left join. In SQL Server, you can use these join clauses in the UPDATE statement to perform a cross-table update. The following illustrates the syntax of the UPDATE JOIN clause: UPDATE t1 SET t1.c1 = t2.c2, t1.c2 = expression, ...
We can force a merge join with a query hint: UPDATE P SET HHID = H.HHID FROM dbo.households AS H JOIN dbo.persons AS P ON P.tempId = H.tempId AND P.n = H.n OPTION (MERGE JOIN); This produces a plan that does not require as much memory (because merge join does not need a hash table):
6 Σεπ 2021 · The general syntax of writing an UPDATE statement with a JOIN. Converting your SELECT statement to an UPDATE statement. Tips and tricks. Also, everything in this tutorial can also be found in the following FREE Ebook: FREE Ebook on SQL Server JOIN Operations!
20 Ιουλ 2017 · A merge join on (col1, col2) can use indexes on (col1, col2) or (col2, col1), but the key order must be the same for both tables. Merge join is most efficient when at least one of the inputs is guaranteed unique on the join keys.
