How to Write or Define a Subquery in Postgres?
Here’s the syntax for nested select statements in PostgreSQL:
Syntax:
SELECT column1, column2, ...
FROM table_name
WHERE column_name OPERATOR (SELECT column_name FROM table_name WHERE condition);
Explanation:
- SELECT column1, column2, … specifies the columns to retrieve in the outer query.
- FROM table_name specifies the table from which to retrieve data in the outer query.
- WHERE column_name OPERATOR (SELECT column_name FROM table_name WHERE condition) is the nested select statement.
- column_name is the column to compare in the outer query.
- OPERATOR is a comparison operator (e.g., =, >, <, IN, EXISTS).
- (SELECT column_name FROM table_name WHERE condition) is the inner query that returns a result set.
What is Nested Select Statement in PostgreSQL?
Nested select statements, also known as subqueries which is a fundamental concept in PostgreSQL and play an important role in data retrieval and manipulation. In PostgreSQL, a powerful relational database management system, the nested select statements allow for complex queries by nesting one query within another.
In this article, We will explore the concept of nested select statements in PostgreSQL by understanding the various examples and so on.