PostgreSQL SELECT LIMIT statement.

Preamble

PostgreSQL SELECT LIMIT statement is used to extract records from one or more tables in PostgreSQL and limit the number of records to be returned based on the Limit limit.

Syntax for SELECT LIMIT in PostgreSQL

SELECT_id
FROM tabs
[WHERE conds]
[ORDER BY expression_id [ ASC | DESC ]].
LIMIT row_count;

Parameters and arguments of the statement

• expressions_id – The table or calculations that you want to get.
• tabs – The tables from which you want to get the records. The FROM operator must specify at least one table.
• WHERE conds – Optional. The conditions that must be met for the entries to be selected.
• ORDER BY expression_id – Optional. It is used in the SELECT LIMIT operator so that you can organize the results and select the records you want to return.
• LIMIT row_count – Sets a limited number of rows in the result set to be returned based on row_count. For example, LIMIT 10 will return the first 10 rows that meet the SELECT criteria. This is where the sort order is important, so be sure to use the ORDER BY operator.

Use the keyword LIMIT

Let’s see how to use the SELECT statement with LIMIT in PostgreSQL.
For example:

SELECT order_id, quantity, price
FROM order_details
WHERE website = 'Google.com'.
ORDER BY order_id DESC
LIMIT 8;

In this PostgreSQL example, SELECT LIMIT will select the first 8 entries from the order_details table, where the website is ‘Google.com’. Note that the results are sorted by order_id in descending order, so this means that the 8 largest order_id values will be returned by SELECT LIMIT.

If there are other entries in the order_details table with the value ‘Google.com’, they will not be returned by the SELECT LIMIT operator in PostgreSQL.

If we wanted to select the 8 smallest order_id values instead of the largest, we could change the sort order as follows:

SELECT order_id, quantity, price
FROM order_details
WHERE website = 'Google.com'.
ORDER BY order_id ASC
LIMIT 8;

Now the results will be sorted by order_id in ascending order, so the first 8 smallest order_id records that have a website – ‘Google.com’, will be returned by this operator SELECT LIMIT. No other entries will be returned by this request.

SQL Limit Clause

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