How to drop Postgres constraint if table exists?

Question

How can I drop fk_bar if its table tbl_foo exists in Postgres and if the constraint itself exists?

I tried

ALTER TABLE IF EXISTS tbl_foo DROP CONSTRAINT IF EXISTS fk_bar;

But that gave me an error when tbl_foo does not exist. It executes successfully if the table does exist.

Works for me. Which Postgres version are you using? (use select version() to find out) — user330315
– user330315, Commented Nov 20, 2017 at 22:48
Actually -- I have another server with 9.2.x and it works there — amphibient
– amphibient, Commented Nov 20, 2017 at 22:54

Vao Tsun · Accepted Answer · 2017-11-21 08:53:11Z

2

ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ]

ALTER TABLE [ ONLY ] name [ * ]

before 9.2 no such syntaxis:

ALTER TABLE IF EXISTS

Add IF EXISTS options to some ALTER commands (Pavel Stehule)

answered Nov 21, 2017 at 8:53

Vao Tsun

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