Difference Between INNER JOIN and LEFT JOIN in Postgresql

INNER JOIN and LEFT JOIN are both types of join operations used in SQL queries in Postgresql.

INNER JOIN:

INNER JOIN only returns rows when there is at least one match found in both tables being joined. If there is no match, the rows are not included in the result set.

LEFT JOIN:

LEFT JOIN returns all rows from the left table and the matched rows from the right table. If there is no match for a row in the right table, NULL values are returned for the columns from the right table.

When to Use Each:

Use INNER JOIN when you only want to retrieve the rows that have matching values in both tables. This is useful for filtering results based on a common column or key.

Use LEFT JOIN when you want to retrieve all rows from the left table regardless of whether there is a match in the right table. This is useful for fetching data even if there are no corresponding entries in the related table.