hi. in postgres you can't so easily change column type.. the documentation of 'alter table' there's no word about changing column type, as if they didn't want to talk about it
for a long time i thought it was only possible by recreating the table, but i found something like this in the faq
Quote:
To change the data type of a column, do this:
BEGIN;
ALTER TABLE tab ADD COLUMN new_col new_data_type;
UPDATE tab SET new_col = CAST(old_col AS new_data_type);
ALTER TABLE tab DROP COLUMN old_col;
COMMIT;
You might then want to do VACUUM FULL tab to reclaim the disk space used by the expired rows.
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