Update with two tables?

The answers didn't work for me with postgresql 9.1+

This is what I had to do (you can check more in the manual here)

UPDATE schema.TableA as A
SET "columnA" = "B"."columnB"
FROM schema.TableB as B
WHERE A.id = B.id;

You can omit the schema, if you are using the default schema for both tables.

Your query does not work because you have no FROM clause that specifies the tables you are aliasing via A/B.

Please try using the following:

UPDATE A
    SET A.NAME = B.NAME
FROM TableNameA A, TableNameB B
WHERE A.ID = B.ID

Personally I prefer to use more explicit join syntax for clarity i.e.

UPDATE A
    SET A.NAME = B.NAME
FROM TableNameA A
    INNER JOIN TableName B ON 
        A.ID = B.ID

For Microsoft Access

UPDATE TableA A
    INNER JOIN TableB B
    ON A.ID = B.ID
SET A.Name = B.Name

I was scratching my head, not being able to get John Sansom's Join syntax work, at least in MySQL 5.5.30 InnoDB.

It turns out that this doesn't work.

UPDATE A 
    SET A.x = 1
FROM A INNER JOIN B 
        ON A.name = B.name
WHERE A.x <> B.x

But this works:

UPDATE A INNER JOIN B 
    ON A.name = B.name
SET A.x = 1
WHERE A.x <> B.x