Hello
I have a performance problem with an SQL statement.
Is there a better way to do this update:
UPDATE table1 SET column2 = temp_table.column2, column3 = temp_table.column3, column4 = CAST(temp_table.column4 AS date) FROM
(
SELECT DISTINCT
table2.column1,
table2.column2,
table2.column3,
table2.column4
FROM table2 WHERE column4 IS NOT NULL AND column4 <> '' AND (length(column4) = 10 OR length(column4) = 23)
) AS temp_table
WHERE table1.column1 = temp_table.column1;
The select by it’s own takes around 1 second. The Update is around 120’000 rows. I got an index on column1. The whole query needs around 16 minutes.
The same procedure on MSSQL needs around 30 seconds. I hope to get it too in Postgres…
Please help me.
Regards
Reto
