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

sql, sql-server, sql-server-2005, sql-update, t-sql

Solution

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. Main question: How to do an update + join in PostgreSQL?

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
 );

SQLite 3.33 added support for an `UPDATE` + `FROM` syntax analogous to the PostgreSQL one:

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

Main question: Update with Join in SQLite

Problem

I need to update this table in SQL Server with data from its 'parent' table, see below: Table: sale ``` id (int) udid (int) assid (int) ``` Table: ud ``` id (int) assid (int) ``` `sale.assid` contains the correct value to update `ud.assid`. What query will do this? I'm thinking of a `join` but I'm not sure if it's possible.

Original source

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