How to do an update + join in PostgreSQL? - postgresql

Question

Basically, I want to do this:
update vehicles_vehicle v
join shipments_shipment s on v.shipment_id=s.id
set v.price=s.price_per_vehicle;
I'm pretty sure that would work in MySQL (my background), but it doesn't seem to work in postgres. The error I get is:
ERROR: syntax error at or near "join"
LINE 1: update vehicles_vehicle v join shipments_shipment s on v.shi...
^
Surely there's an easy way to do this, but I can't find the proper syntax. So, how would I write this In PostgreSQL?

Answer 1

The UPDATE syntax is:
[ WITH [ RECURSIVE ] with_query [, ...] ]
UPDATE [ ONLY ] table [ [ AS ] alias ]
SET { column = { expression | DEFAULT } |
( column [, ...] ) = ( { expression | DEFAULT } [, ...] ) } [, ...]
[ FROM from_list ]
[ WHERE condition | WHERE CURRENT OF cursor_name ]
[ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]
In your case I think you want this:
UPDATE vehicles_vehicle AS v
SET price = s.price_per_vehicle
FROM shipments_shipment AS s
WHERE v.shipment_id = s.id
Or if you need to join on two or more tables:
UPDATE table_1 t1
SET foo = 'new_value'
FROM table_2 t2
JOIN table_3 t3 ON t3.id = t2.t3_id
WHERE
t2.id = t1.t2_id
AND t3.bar = True;

Answer 2

The answer of Mark Byers is the optimal in this situation.
Though in more complex situations you can take the select query that returns rowids and calculated values and attach it to the update query like this:
with t as (
-- Any generic query which returns rowid and corresponding calculated values
select t1.id as rowid, f(t2, t2) as calculatedvalue
from table1 as t1
join table2 as t2 on t2.referenceid = t1.id
)
update table1
set value = t.calculatedvalue
from t
where id = t.rowid
This approach lets you develop and test your select query and in two steps convert it to the update query.
So in your case the result query will be:
with t as (
select v.id as rowid, s.price_per_vehicle as calculatedvalue
from vehicles_vehicle v
join shipments_shipment s on v.shipment_id = s.id
)
update vehicles_vehicle
set price = t.calculatedvalue
from t
where id = t.rowid
Note that column aliases are mandatory otherwise PostgreSQL will complain about the ambiguity of the column names.

Answer 3

Let me explain a little more by my example.
Task: correct info, where abiturients (students about to leave secondary school) have submitted applications to university earlier, than they got school certificates (yes, they got certificates earlier, than they were issued (by certificate date specified). So, we will increase application submit date to fit certificate issue date.
Thus. next MySQL-like statement:
UPDATE applications a
JOIN (
SELECT ap.id, ab.certificate_issued_at
FROM abiturients ab
JOIN applications ap
ON ab.id = ap.abiturient_id
WHERE ap.documents_taken_at::date < ab.certificate_issued_at
) b
ON a.id = b.id
SET a.documents_taken_at = b.certificate_issued_at;
Becomes PostgreSQL-like in such a way
UPDATE applications a
SET documents_taken_at = b.certificate_issued_at -- we can reference joined table here
FROM abiturients b -- joined table
WHERE
a.abiturient_id = b.id AND -- JOIN ON clause
a.documents_taken_at::date < b.certificate_issued_at -- Subquery WHERE
As you can see, original subquery JOIN's ON clause have become one of WHERE conditions, which is conjucted by AND with others, which have been moved from subquery with no changes. And there is no more need to JOIN table with itself (as it was in subquery).

Answer 4

For those actually wanting to do a JOIN you can also use:
UPDATE a
SET price = b_alias.unit_price
FROM a AS a_alias
LEFT JOIN b AS b_alias ON a_alias.b_fk = b_alias.id
WHERE a_alias.unit_name LIKE 'some_value'
AND a.id = a_alias.id;
You can use the a_alias in the SET section on the right of the equals sign if needed.
The fields on the left of the equals sign don't require a table reference as they are deemed to be from the original "a" table.

Answer 5

For those wanting to do a JOIN that updates ONLY the rows your join returns use:
UPDATE a
SET price = b_alias.unit_price
FROM a AS a_alias
LEFT JOIN b AS b_alias ON a_alias.b_fk = b_alias.id
WHERE a_alias.unit_name LIKE 'some_value'
AND a.id = a_alias.id
--the below line is critical for updating ONLY joined rows
AND a.pk_id = a_alias.pk_id;
This was mentioned above but only through a comment..Since it's critical to getting the correct result posting NEW answer that Works

Answer 6

Here we go:
update vehicles_vehicle v
set price=s.price_per_vehicle
from shipments_shipment s
where v.shipment_id=s.id;
Simple as I could make it.

Answer 7

To add something quite important to all the great answers above, when you want to update a join-table, you may have 2 problems:
you cannot use the table you want to update to JOIN another one
Postgres wants a ON clause after the JOIN so you cannot only use where clauses.
This means that basically, the following queries are not valid:
UPDATE join_a_b
SET count = 10
FROM a
JOIN b on b.id = join_a_b.b_id -- Not valid since join_a_b is used here
WHERE a.id = join_a_b.a_id
AND a.name = 'A'
AND b.name = 'B'
UPDATE join_a_b
SET count = 10
FROM a
JOIN b -- Not valid since there is no ON clause
WHERE a.id = join_a_b.a_id
AND b.id = join_a_b.b_id
a.name = 'A'
AND b.name = 'B'
Instead, you must use all the tables in the FROM clause like this:
UPDATE join_a_b
SET count = 10
FROM a, b
WHERE a.id = join_a_b.a_id
AND b.id = join_a_b.b_id
AND a.name = 'A'
AND b.name = 'B'
It might be straightforward for some but I got stuck on this problem wondering what's going on so hopefully, it will help others.

Answer 8

Here's a simple SQL that updates Mid_Name on the Name3 table using the Middle_Name field from Name:
update name3
set mid_name = name.middle_name
from name
where name3.person_id = name.person_id;

Answer 9

The link below has a example that resolve and helps understant better how use update and join with postgres.
UPDATE product
SET net_price = price - price * discount
FROM
product_segment
WHERE
product.segment_id = product_segment.id;
See: http://www.postgresqltutorial.com/postgresql-update-join/

Answer 10

First Table Name: tbl_table1 (tab1).
Second Table Name: tbl_table2 (tab2).
Set the tbl_table1's ac_status column to "INACTIVE"
update common.tbl_table1 as tab1
set ac_status= 'INACTIVE' --tbl_table1's "ac_status"
from common.tbl_table2 as tab2
where tab1.ref_id= '1111111'
and tab2.rel_type= 'CUSTOMER';

Answer 11

To UPDATE one Table using another, in PostGRE SQL / AWS (SQL workbench).
In PostGRE SQL, this is how you need to use joins in UPDATE Query:
UPDATE TABLEA set COLUMN_FROM_TABLEA = COLUMN_FROM_TABLEB FROM TABLEA,TABLEB WHERE FILTER_FROM_TABLEA = FILTER_FROM_TABLEB;
Example:
Update Employees Set Date_Of_Exit = Exit_Date_Recorded , Exit_Flg = 1 From Employees, Employee_Exit_Clearance Where Emp_ID = Exit_Emp_ID
Table A - Employees Columns in Table A - Date_Of_Exit,Emp_ID,Exit_Flg Table B is - Employee_Exit_Clearance Columns in Table B - Exit_Date_Recorded,Exit_Emp_ID
1760 rows affected
Execution time: 29.18s

Answer 12

--goal: update selected columns with join (postgres)--
UPDATE table1 t1
SET column1 = 'data'
FROM table1
RIGHT JOIN table2
ON table2.id = table1.id
WHERE t1.id IN
(SELECT table2.id FROM table2 WHERE table2.column2 = 12345)

Answer 13

The first way is slower than the second way.
First:
DO $$
DECLARE
page int := 10000;
min_id bigint; max_id bigint;
BEGIN
SELECT max(id),min(id) INTO max_id,min_id FROM opportunities;
FOR j IN min_id..max_id BY page LOOP
UPDATE opportunities SET sec_type = 'Unsec'
FROM opportunities AS opp
INNER JOIN accounts AS acc
ON opp.account_id = acc.id
WHERE acc.borrower = true
AND opp.sec_type IS NULL
AND opp.id >= j AND opp.id < j+page;
COMMIT;
END LOOP;
END; $$;
Second:
DO $$
DECLARE
page int := 10000;
min_id bigint; max_id bigint;
BEGIN
SELECT max(id),min(id) INTO max_id,min_id FROM opportunities;
FOR j IN min_id..max_id BY page LOOP
UPDATE opportunities AS opp
SET sec_type = 'Unsec'
FROM accounts AS acc
WHERE opp.account_id = acc.id
AND opp.sec_type IS NULL
AND acc.borrower = true
AND opp.id >= j AND opp.id < j+page;
COMMIT;
END LOOP;
END; $$;

Answer 14

WORKS PERFECT!!!
POSTGRE SQL - UPDATE With a JOIN
BELOW CODE - Check the positioning of columns and IDs as below:
If you place it exactly as below, then only it will work!
---IF you want to update FIRST table
UPDATE table1
SET attribute1 = table2.attribute1
FROM table2
WHERE table2.product_ID = table1.product_ID;
OR
---IF you want to update SECOND table
UPDATE table2
SET attribute1 = table1.attribute1
FROM table1
WHERE table1.product_ID = table2.product_ID;