https://www.postgresqltutorial.com › postgresql-tutorial › postgresql-exists

The EXISTS operator is a boolean operator that checks the existence of rows in a subquery. Here’s the basic syntax of the EXISTS operator: EXISTS (subquery) Typically, you use the EXISTS operator in the WHERE clause of a SELECT statement: SELECT . select_list . FROM . table1 . WHERE EXISTS ( SELECT . select_list . FROM . table2 . WHERE .

https://stackoverflow.com › questions › 7471625

I have a bunch of rows that I need to insert into table, but these inserts are always done in batches. So I want to check if a single row from the batch exists in the table because then I know they...

https://stackoverflow.com › questions › 11892233

I'm writing a function in PL/pgSQL, and I'm looking for the simplest way to check if a row exists. Right now I'm SELECTing an integer into a boolean, which doesn't really work. I'm not experienced with PL/pgSQL enough yet to know the best way of doing this. Here's part of my function: FROM "people" p. -- Do something.

https://www.postgresql.org › docs › current › functions-subquery.htm

EXISTS (subquery) The argument of EXISTS is an arbitrary SELECT statement, or subquery. The subquery is evaluated to determine whether it returns any rows. If it returns at least one row, the result of EXISTS is “ true ”; if the subquery returns no rows, the result of EXISTS is “ false ”.

https://postgresql-tutorial.com › postgresql-exists-operator

The EXISTS operator is used to check for the existence of rows that satisfy a specified condition within a subquery. The EXISTS operator returns a Boolean value (TRUE or FALSE) based on whether the subquery returns any rows.

https://www.w3schools.com › postgresql › postgresql_exists.php

The EXISTS operator is used to test for the existence of any record in a sub query. The EXISTS operator returns TRUE if the sub query returns one or more records.

https://www.sqliz.com › postgresql › exists

The EXISTS is a unary operator that takes a subquery subquery as an argument. If the subquery subquery returns at least one row (regardless of whether the value in the row is NULL), EXISTS returns TRUE, otherwise returns FALSE.

https://www.techonthenet.com › postgresql › exists.php

This PostgreSQL tutorial explains how to use the PostgreSQL EXISTS condition with syntax and examples. The PostgreSQL EXISTS condition is used in combination with a subquery and is considered to be met if the subquery returns at least one row.

https://www.devanddep.com › tutorial › postgresql › postgresql-exists-operator.html

The EXISTS operator in PostgreSQL is used in the SQL queries to determine if a result set, derived from a subquery, contains any rows. It returns true if the subquery returns one or more rows and false if the subquery returns no rows.

https://tableplus.com › blog › 2018 › 07 › postgresql-how-to-check-if-a-row-exists.html

You have a table address and want to check if there’s already a row with address_id = 100 existing. You can use COUNT to check: SELECT COUNT(*) FROM address WHERE address_id = 100;