How can I do an UPDATE statement with JOIN in SQL Server?

Question

I need to update this table in SQL Server with data from its \'parent\' table, see below:

Table: sale

id (int)
udid         


        

Answer 1

postgres

UPDATE table1
SET    COLUMN = value
FROM   table2,
       table3
WHERE  table1.column_id = table2.id
       AND table1.column_id = table3.id
       AND table1.COLUMN = value
       AND table2.COLUMN = value
       AND table3.COLUMN = value 

Answer 2

MySQL

You'll get the best performance if you forget the where clause and place all conditions in the ON expression.

I think this is because the query first has to join the tables then runs the where clause on that, so if you can reduce what is required to join then that's the fasted way to get the results/do the udpate.

Example

Scenario

You have a table of users. They can log in using their username or email or account_number. These accounts can be active (1) or inactive (0). This table has 50000 rows

You then have a table of users to disable at one go because you find out they've all done something bad. This table however, has one column with usernames, emails and account numbers mixed. It also has a "has_run" indicator which needs to be set to 1 (true) when it has been run

Query

UPDATE users User
    INNER JOIN
        blacklist_users BlacklistUser
        ON
        (
            User.username = BlacklistUser.account_ref
            OR
            User.email = BlacklistedUser.account_ref
            OR
            User.phone_number = BlacklistUser.account_ref
            AND
            User.is_active = 1
            AND
            BlacklistUser.has_run = 0
        )
    SET
        User.is_active = 0,
        BlacklistUser.has_run = 1;

Reasoning

If we had to join on just the OR conditions it would essentially need to check each row 4 times to see if it should join, and potentially return a lot more rows. However, by giving it more conditions it can "skip" a lot of rows if they don't meet all the conditions when joining.

Bonus

It's more readable. All the conditions are in one place and the rows to update are in one place

Answer 3

For SQLite use the RowID property to make the update:

update Table set column = 'NewValue'
where RowID = 
(select t1.RowID from Table t1
join Table2 t2 on t1.JoinField = t2.JoinField
where t2.SelectValue = 'FooMyBarPlease');

Answer 4

UPDATE tblAppraisalBasicData
SET tblAppraisalBasicData.ISCbo=1
FROM tblAppraisalBasicData SI INNER JOIN  aaa_test RAN ON SI.EmpID = RAN.ID

Answer 5

Syntax strictly depends on which SQL DBMS you're using. Here are some ways to do it in ANSI/ISO (aka should work on any SQL DBMS), MySQL, SQL Server, and Oracle. Be advised that my suggested ANSI/ISO method will typically be much slower than the other two methods, but if you're using a SQL DBMS other than MySQL, SQL Server, or Oracle, then it may be the only way to go (e.g. if your SQL DBMS doesn't support MERGE):

ANSI/ISO:

update ud 
     set assid = (
          select sale.assid 
          from sale 
          where sale.udid = ud.id
     )
 where exists (
      select * 
      from sale 
      where sale.udid = ud.id
 );

MySQL:

update ud u
inner join sale s on
    u.id = s.udid
set u.assid = s.assid

SQL Server:

update u
set u.assid = s.assid
from ud u
    inner join sale s on
        u.id = s.udid

PostgreSQL:

update ud
  set assid = s.assid
from sale s 
where ud.id = s.udid;

Note that the target table must not be repeated in the FROM clause for Postgres.

Oracle:

update
    (select
        u.assid as new_assid,
        s.assid as old_assid
    from ud u
        inner join sale s on
            u.id = s.udid) up
set up.new_assid = up.old_assid

SQLite:

update ud 
     set assid = (
          select sale.assid 
          from sale 
          where sale.udid = ud.id
     )
 where RowID in (
      select RowID 
      from ud 
      where sale.udid = ud.id
 );

Answer 6

A standard SQL approach would be

UPDATE ud
SET assid = (SELECT assid FROM sale s WHERE ud.id=s.id)

On SQL Server you can use a join

UPDATE ud
SET assid = s.assid
FROM ud u
JOIN sale s ON u.id=s.id