Read the detailed explanation over there and pick the approach that best fits your use case. UPDATE bank SET Address 2,'PANCard' 3,'IFSC' 4 WHERE userid 1 INSERT INTO bank (userid,bankdetails,'PAN',bankacc,'UAN',tax) SELECT '2','3','4','5','6' WHERE NOT. Especially if the row frequently already exists, this is a bit faster. INSERT INTO tag ('key', 'value') SELECT 'key1', 'value1' WHERE NOT EXISTS ( SELECT id,'key','value' FROM tag WHERE key 'key1' AND value 'value1') which works in the sense that it doesn't insert if exists, but I'd like to get the id. How to perform update and insert in same query i need to update the record, if it is not present then it has to perform insertion i tried this. So here the overhead is slightly smaller (simpler queries), but the time frame for a race condition is slightly bigger. The alternative with CTEs runs as one SQL statement. role does not exist psql postgres return id after insert check table exist postgresql postgres create extension if not exists how to check table exists or not in postgresql psql fatal database does not exist check table exist postgresql fatal database postgres does not exist insert or ignore postgres postgres create database if not. This is assuming a UNIQUE constraint (or a UNIQUE index) on email, obviously. You only need the loop to deal with a possible race condition: If a concurrent transaction writes the same email value in between SELECT and INSERT, you would get a unique violation - which is handled properly here. RAISE NOTICE 'It actually happened!' - hardly ever happensĮXIT WHEN email_id IS NOT NULL - else keep looping RETURNING mailing_list.email_id INTO email_id ĮXCEPTION WHEN UNIQUE_VIOLATION THEN - inserted in concurrent session. If the standard practice is to always either insert or update if exists, why is. INSERT INTO mailing_list (email) VALUES (_email) but Im wondering just how to get the id if it exists, instead of updating. SELECT INTO email_id m.email_id FROM mailing_list m WHERE m.email = _email Is SELECT or INSERT in a function prone to race conditions?ĬREATE OR REPLACE FUNCTION f_email_insel(_email text, OUT email_id int) ASīEGIN - start inner block inside loop to handle possible exception The PostgreSQL EXISTS condition is used to check the existence of rows from the result set of the subquery by combining with a subquery, which is acceptable even if the result set is returned by the subquery contains at least one row which means the PostgreSQL EXISTS works with a subquery. Here is a simple variant of the related version we have been referring to: Where not exists (select * from Test1 as t where t.key = v.key and t.value = v.Already explained how to avoid the error message you saw. Unless one or both of the "key"/"value" pair can be null. It's based on Common Table Expressions (CTEs) and that fact that with PostgreSQL, you can perform not only SELECTs, but also INSERTs, UPDATEs and DELETEs (see here also). If the row does not exist it will return the inserted one else the existing one.īTW, if the pair "key"/"value" makes it unique then it is the primary key, and there is no need for an id column. To return the row if it already exists with s as ( This Wiki page was only maintained until a few weeks before commit, where the patch further evolved in some minor aspects (most notably, the syntax became ON CONFLICT DO UPDATE/NOTHING). The patch has been committed 1, and will appear in PostgreSQL 9.5. Yes there is returning INSERT INTO tag ("key", "value") 4 Answers Sorted by: 72 You can use an outer join against a values list (similar to Martin's answer mentioned above): select t.id from ( values (4), (5), (6) ) as t (id) left join images i on i.id t.id where i. This feature is popularly known as 'UPSERT'.
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