UPDATE with multiple WHERE conditions

Greetings,

You can use Temporary table. You could create a temporary table with one
column containing the condition values and then use it to update your main
table. This approach can be more flexible and cleaner than writing a script
with multiple update statements.

-- Create a temporary table with one column containing the condition values
CREATE TEMPORARY TABLE temp_conditions (condition_value TEXT);

-- Insert the condition values into the temporary table
INSERT INTO temp_conditions (condition_value) VALUES
('value1'),
('value2'),
('value3'),
-- Add more values as needed...
('value295');

-- Update the boolean column based on the condition values
UPDATE your_table
SET boolean_column = true
WHERE condition_column IN (SELECT condition_value FROM temp_conditions);

-- Clean up: drop the temporary table
DROP TABLE IF EXISTS temp_conditions;

*Salahuddin (살라후딘**)*

On Thu, 13 Jun 2024 at 02:28, Rich Shepard <rshepard@appl-ecosys.com> wrote:

On Thu, 13 Jun 2024, Muhammad Salahuddin Manzoor wrote:

You can use Temporary table. You could create a temporary table with one
column containing the condition values and then use it to update your main
table. This approach can be more flexible and cleaner than writing a
script with multiple update statements.

Salahuddin,

Thank you. I thought this would be the best approach.

Regards,

Rich

On Wed, Jun 12, 2024 at 5:28 PM Rich Shepard <rshepard@appl-ecosys.com>
wrote:

I have a table with 3492 rows. I want to update a boolean column from
'false' to 'true' for 295 rows based on the value of another column.

Is there a way to access a file with those condition values? If not, should
I create a temporary table with one column containing those values, or do I
write a psql script with 295 lines, one for each row to be updated?

A plain UPDATE might work.

UPDATE to_be_updated a
SET bool_col = true
FROM other_table b
WHERE a.pk = b.pk
AND b.field3 = mumble;

(You can join them, right?)

On 6/12/24 15:48, Ron Johnson wrote:

On Wed, Jun 12, 2024 at 5:28 PM Rich Shepard
<rshepard@appl-ecosys.com> wrote:

I have a table with 3492 rows. I want to update a boolean column from
'false' to 'true' for 295 rows based on the value of another column.

Is there a way to access a file with those condition values? If
not, should
I create a temporary table with one column containing those
values, or do I
write a psql script with 295 lines, one for each row to be updated?

A plain UPDATE might work.
UPDATE to_be_updated a
SET bool_col = true
FROM other_table b
WHERE a.pk <http://a.pk&gt; = b.pk <http://b.pk&gt;
  AND b.field3 = mumble;

(You can join them, right?)

Add "begin;" to that and try it.  If you don't get exactly UPDATE 295
reported, then "rollback;";

On Wed, Jun 12, 2024 at 2:28 PM Rich Shepard <rshepard@appl-ecosys.com>
wrote:

I have a table with 3492 rows. I want to update a boolean column from
'false' to 'true' for 295 rows based on the value of another column.

Is there a way to access a file with those condition values?

I'll often just use a spreadsheet to build the 295 update commands and
copy-paste them into psql or whatnot.

David J.

On Wed, 12 Jun 2024, David G. Johnston wrote:

I'll often just use a spreadsheet to build the 295 update commands and
copy-paste them into psql or whatnot.

David,

I'll create and use a temporary table.

Thanks,

Rich

On Wed, 12 Jun 2024, Ron Johnson wrote:

A plain UPDATE might work.

UPDATE to_be_updated a
SET bool_col = true
FROM other_table b
WHERE a.pk = b.pk
AND b.field3 = mumble;

(You can join them, right?)

Thanks, Ron.

Rich

On Wed, 12 Jun 2024, Rob Sargent wrote:

Add "begin;" to that and try it.  If you don't get exactly UPDATE 295
reported, then "rollback;";

Got it, thanks.

Rich

On 2024-Jun-12, David G. Johnston wrote:

On Wed, Jun 12, 2024 at 2:28 PM Rich Shepard <rshepard@appl-ecosys.com>
wrote:

I have a table with 3492 rows. I want to update a boolean column from
'false' to 'true' for 295 rows based on the value of another column.

I'll often just use a spreadsheet to build the 295 update commands and
copy-paste them into psql or whatnot.

A closely related technique: if you have a query that generates the
UPDATE commands you need, you can run it under \gexec in psql, and
they'll be executed.

--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
Al principio era UNIX, y UNIX habló y dijo: "Hello world\n".
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