SQL update statements updates wrong fields - postgresql

I have the following code in Postgres
select op.url from identity.legal_entity le
join identity.profile op on le.legal_entity_id =op.legal_entity_id
where op.global_id = '8wyvr9wkd7kpg1n0q4klhkc4g'
which returns 1 row.
Then I try to update the url field with the following:
update identity.profile
set url = 'htpp:sam'
where identity.profile.url in (
select op.url from identity.legal_entity le
join identity.profile op on le.legal_entity_id =op.legal_entity_id
where global_id = '8wyvr9wkd7kpg1n0q4klhkc4g'
);
But the above ends up updating more than 1 row, actually all of the rows of the identity table.
I would assume since the first postgres statement returns one row, only one row at most can be updated, but I am getting the wrong effect where all of the rows are being updated. Why ?? Please help a nubie fix the above update statement.

Instead of using profile.url to identify the row you want to update, use the primary key. That is what it is there for.
So if the primary key column is called id, the statement could be modified to:
UPDATE identity.profile
SET ...
WHERE identity.profile.id IN (SELECT op.id FROM ...);
But you can do this much simpler in PostgreSQL with
UPDATE identity.profile op
SET url = 'htpp:sam'
FROM identity.legal_entity le
WHERE le.legal_entity_id = op.legal_entity_id
AND le.global_id = '8wyvr9wkd7kpg1n0q4klhkc4g';

Related

PostgreSQL transforming the entire column value in a table

I have been trying to change all the values in a column. When I do it turns out to take my table and drop all the rows that match my criteria in the where clause.
Example
|_Month_|_Cost_|_Title_|
|___2___|_15.99|_hello_|
|___2___|_32.87|_John__|
|___2___|_32.87|_Neat__|
|___3___|_32.87|_Kelps_|
|___4___|_32.87|_Gulp__|
|___5___|_32.87|_Tried_|
I run this Query
UPDATE tableName SET Month = 'FEB' WHERE Month = 2;
The Change:
|_Month_|_Cost_|_Title_|
|__FEB__|_32.87|_Neat__|
|___3___|_32.87|_Kelps_|
|___4___|_32.87|_Gulp__|
|___5___|_32.87|_Tried_|
What I need:
|_Month_|_Cost_|_Title_|
|__FEB__|_15.99|_hello_|
|__FEB__|_32.87|_John__|
|__FEB__|_32.87|_Neat__|
|___3___|_32.87|_Kelps_|
|___4___|_32.87|_Gulp__|
|___5___|_32.87|_Tried_|
Where am I going wrong?
I have also tried to get the date changed from a timestamp with
SELECT TO_DATE(payment_timestamp, 'Mon") payment_month
from tablename;
but PostgreSQL doesn't recognize the TO_DATE()?? Can someone tell me why?

Multipart column names in update statement with select

I'm sure this could be a duplicate but I can't seem to find the right search phrase.
Given a table in a named schema (i.e. not dbo) requires you include the schema name in the statement. So previously I'd have simply written it as so:
UPDATE [Schema].[Table1]
SET [AColumn] =
(
SELECT [SomeColumn]
FROM [Schema].[Table2]
WHERE [Schema].[Table2].[SameColumnName] = [Schema].[Table1].[SameColumnName]
);
But since More than two-part column name is deprecated, I need to find a new way to do this which is future proof. I have come up with 2 options, firstly using an alias:
UPDATE [Alias1]
SET [AColumn] =
(
SELECT [SomeColumn]
FROM [Schema].[Table2] [Alias2]
WHERE [Alias2].[SameColumnName] = [Alias1].[SameColumnName]
)
FROM [Schema].[Table1] [Alias1];
The second way is the one I'm really having trouble finding out if it's truly VALID T-Sql:
UPDATE [Schema].[Table1]
SET [AColumn] =
(
SELECT [SomeColumn]
FROM [Schema].[Table2]
WHERE [Table2].[SameColumnName] = [Table1].[SameColumnName]
);
I have tested both and they work, so my question is, is the second completely valid and normal to use just the table name without the Schema in this sense or should I rather opt for the slightly more verbose Alias?
As I said in my comment, alias your objects.
SELECT MT.MyColumn,
YT.MyColumn
FROM dbo.MyTable MT
JOIN so.YourTable YT ON MT.ID = YT.fID
WHERE YT.[name] = N'Jane';
If you're performing an UPDATE, then specify the alias of the object to Update:
UPDATE MT
SET MyColumn = YT.MyColumn --Column on the left side of the SET will always reference the table being updated
FROM dbo.MyTable MT
JOIN so.YourTable YT ON MT.ID = YT.fID
WHERE YT.[name] = N'Jane';

Postgresql - Rule with On Conflict Statement

I have a table in postgres with columns link(PK), person, places and date. I would like to create a rule that when insert is command is issued from my backend program then if there is a conflict on the link column it would do an upsert ( update the person, places and date) columns for the same link. I cannot figure out the format of the rule. Below is pseudo code of what I am looking for.
Create Rule rssmodel as on
INSERT into public.rssmodel
On conflict (link)
do UPDATE public.rssmodel
set person = data, places=data, date=data
You could do something like this to achieve that:
CREATE RULE rssmodel_insert AS ON
INSERT TO public.rssmodel
WHERE EXISTS (SELECT 1 from rssmodel where NEW.link = link)
DO INSTEAD
UPDATE public.rssmodel
SET person = NEW.person, places = NEW.places, date = NEW.date WHERE link = NEW.link;

Postgres Update Using Select Passing In Parent Variable

I need to update a few thousand rows in my Postgres table using the result of a array_agg and spatial lookup.
The query needs to take the geometry of the parent table, and return an array of the matching row IDs in the other table. It may return no IDs or potentially 2-3 IDs.
I've tried to use an UPDATE FROM but I can't seem to pass into the subquery the parent table geom column for the SELECT. I can't see any way of doing a JOIN between the 2 tables.
Here is what I currently have:
UPDATE lrc_wales_data.records
SET lrc_array = subquery.lrc_array
FROM (
SELECT array_agg(wales_lrcs.gid) AS lrc_array
FROM layers.wales_lrcs
WHERE st_dwithin(records.geom_poly, wales_lrcs.geom, 0)
) AS subquery
WHERE records.lrc = 'nrw';
The error I get is:
ERROR: invalid reference to FROM-clause entry for table "records"
LINE 7: WHERE st_dwithin(records.geom_poly, wales_lrcs.geom, 0)
Is this even possible?
Many thanks,
Steve
Realised there was no need to use SET FROM. I could just use a sub query directly in the SET:
UPDATE lrc_wales_data.records
SET lrc_array = (
SELECT array_agg(wales_lrcs.gid) AS lrc
FROM layers.wales_lrcs
WHERE st_dwithin(records.geom_poly, wales_lrcs.geom, 0)
)
WHERE records.lrc = 'nrw';

Updating records in Postgres using nested sub-selects

I have a table where I have added a new column, and I want to write a SQL statement to update that column based on existing information. Here are the two tables and the relevant columns
'leagues'
=> id
=> league_key
=> league_id (this is the new column)
'permissions'
=> id
=> league_key
Now, what I want to do, in plain English, is this
Set leagues.league_id to be permissions.id for each value of permissions.league_key
I had tried SQL like this:
UPDATE leagues
SET league_id =
(SELECT id FROM permissions WHERE league_key =
(SELECT distinct(league_key) FROM leagues))
WHERE league_key = (SELECT distinct(league_key) FROM leagues)
but I am getting an error message that says
ERROR: more than one row returned by a subquery used as an expression
Any help for this would be greatly appreciated
Based on your requirements of
Set leagues.league_id to be permissions.id for each value of permissions.league_key
This does that.
UPDATE leagues
SET league_id = permissions_id
FROM permissions
WHERE permissions.league_key = leagues.league_key;
When you do a subquery as an expression, it can't return a result set. Your subquery must evaluate to a single result. The error that you are seeing is because one of your subqueries returns more than one value.
Here is the relevant documentation for pg84: