How to limit the results on a SQL query

Answer 1

SQL Standard

As I explained in this article, the SQL:2008 Standard provides the following syntax to limit the SQL result set:

SELECT
    title
FROM
    post
ORDER BY
    id DESC
FETCH FIRST 50 ROWS ONLY

The SQL:2008 Top-N records clause is supported in Oracle since 12c, SQL Server since 2012, and PostgreSQL since 8.4.

SQL Server

While SQL Server supports the SQL:2008 Top-N standard syntax, you need to provide the OFFSET clause as well:

SELECT
    title
FROM
    post
ORDER BY
    id DESC
OFFSET 0 ROWS
FETCH FIRST 50 ROWS ONLY

On older SQL Server versions, you can use TOP:

SELECT TOP 50
    title
FROM
    post
ORDER BY
    id DESC

Oracle 11g and older versions

Prior to version 12c, to fetch the Top-N records, you had to use a derived table and the ROWNUM pseudocolumn:

SELECT *
FROM (
    SELECT
        title
    FROM
        post
    ORDER BY
        id DESC
)
WHERE ROWNUM <= 50

MySQL and PostgreSQL 8.3 or older

Traditionally, MySQL and PostgreSQL use the LIMIT clause to restrict the result set to the Top-N records:

SELECT
    title
FROM
    post
ORDER BY
    id DESC
LIMIT 50