Postgresql – Update all columns from another table

postgresqlupdate

I need to update a table from another one, and I need to update all columns. Besides listing every column in the SET clause, is there a way to update them all at once? Like this:

update tableA
set * = tableB.*
from tableB where tableA.id = tableB.id

I tried in psql, it doesn't work. I have to list every column like this:

update tableA
set c1 = tableB.c1, c2 = tableB.c2, ...
from tableB where tableA.id = tableB.id

tableB is created use create .. like tableA. So they are basically identical. And the reason I'm doing it is that I need to load .csv data to a temp table tableB and then update tableA based on the new data in tableB. tableA needs to be locked as little as possible and tableA needs to keep integrity. I'm not sure 'delete then insert' would be a good option?

Best Answer

There is no syntax variant that lets you update the whole row at once. However, there is a shorter form than what you have so far.

Also, you do not actually want to update all columns. The WHERE condition on id pins down at least one column (id) to remain unchanged. But that's just nitpicking.

UPDATE table_a a
SET    (  c1,   c2, ...)
     = (b.c1, b.c2, ...)
FROM   table_b b
WHERE  a.id = b.id;

More details in this related answer:
Bulk update of all columns

`DELETE / INSERT`

Internally, due to the MVCC model of Postgres, every UPDATE effectively inserts a new row anyway and marks the old one as obsolete. So, behind the curtains there is not much difference between UPDATE and DELETE plus INSERT.
There are some details in favor of the UPDATE route:

HOT UPDATE.
TOAST tables: If you have large columns, the content may be stored."out-of-line" in TOAST tables and the new row version can link to the same row in the TOAST table if toasted columns remain unchanged.
Index maintenance may be cheaper for updates.

Otherwise, locking should be about the same. You need an exclusive lock on affected rows either way. Just make it quick.
If you are dealing with a huge number of rows and you don't need a consistent state (all rows or none), you can split the operation into multiple batches. (Separate transactions!) Increases the total cost, but keeps the lock time per row shorter.

OPTION #1 : INSERT INTO ... ON DUPLICATE KEY UPDATE

INSERT INTO newtable
SELECT * FROM oldtable
ORDER BY tmstamp_value
ON DUPLICATE KEY UPDATE email=VALUES(email), address=VALUES(address) ... ;

OPTION #2 : REPLACE INTO

REPLACE INTO newtable
SELECT * FROM oldtable
ORDER BY tmstamp_value;

It mechanically performs a DELETE and an INSERT.

CAVEAT

Notice I applied the ORDER BY against the old table. This should help get the latest data for a give LastName, FirstName.

You should also add a UNIQUE INDEX on the new table as follows:

ALTER TABLE newtable ADD UNIQUE INDEX name_ndx (lastname,firstname);

UPDATE 2013-04-08 17:13 EDT

If you are doing updates, there are two ways to do this:

1. UPDATE JOIN

UPDATE
(SELECT lastname,firstname,phone,email
FROM oldtable ORDER BY lastname,firstname) A
LEFT JOIN newtable B USING (lastname,firstname)
SET B.phone=A.phone,B.email=A.email;

2. UPDATE JOIN with GROUP BY

UPDATE
(
    SELECT BB.id,BB.phone,BB.email FROM 
    (SELECT lastname,firstname,MAX(id) id FROM oldtable GROUP BY lastname,firstname) AA
    INNER JOIN oldtable BB USING (lastname,firstname)
) A INNER JOIN newtable B USING (id)
SET B.phone=A.phone,B.email=A.email;

Give it a Try !!!

Both options will take full advantage of the UNIQUE index on name.

Postgresql – Bulk update of all columns

If you only want to update data, I'm not sure what the INSERT statement is for in your question.

If you just want to update several rows with a single statement, you might be looking for this:

with update_values (ID,PARENT_ID,BOUGHT_IN_FORM_TYPE_ID,PRIORITY,NAME,HEADING,DESCRIPTION,ICON,BOUGHT_IN_CONTROL_PANEL_FILE_ID) as 
(
  VALUES
     (109,1,28,100,'Tooling','Tooling','Enter your Machine Tools here','tooling.png',null), 
     (1,0,1,200,'Bought In','Bought In','','boughtin.png',null)
)
update bought_in_control_panel
   set parent_id = ud.parent_id, 
       bought_in_form_type_id = ud.bought_in_form_type_id,
       ....
from update_values ud
where ud.id = bought_in_control_panel.id;

Best Answer

DELETE / INSERT

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