Introduction to PostgreSQL LIMIT
PostgreSQL limit clause returns the number of rows from table which was mentioned in limit value at the time of fetching record from the table. It is an optional clause of PostgreSQL select statement, used to fetch limited no of rows from the whole table, this clause is also used with offset clause to fetch record from table. We can use this clause with an order by clause to find ascending and descending number, it is the best way to find the top and bottom value of rows using limit clause in PostgreSQL.
Syntax:
1. PostgreSQL Limit clause
Select column_name1, …, column_nameN from table_name LIMIT N (Number of rows count)
Select * (select all table columns) from table_name LIMIT N (Number of rows count)
2. Limit clause using offset clause
Select column_name1, …, column_nameN from table_name LIMIT N (Number of rows count) OFFSET N (Number of offset)
Select * (select all table columns) from table_name LIMIT N (Number of rows count) OFFSET N (Number of offset)
3. Using order by clause
Select column_name1, …, column_nameN from table_name ORDER BY column_name LIMIT N (Number of rows count)
Select column_name1, …, column_nameN from table_name ORDER BY column_name LIMIT N (Number of rows count) OFFSET N (Number of offset)
Select column_name1, …, column_nameN from table_name ORDER BY column_name DESC LIMIT N (Number of rows count)
Select column_name1, …, column_nameN from table_name ORDER BY column_name ASC LIMIT N (Number of rows count)
Parameter description of the above syntax is as follows:
- Select: Select statement is used to select no of rows using the limit clause.
- Column_name1 to column_nameN: We are selecting a column to fetch data from table using limit clause.
- From: Keyword used to select specified table to fetch data using limit clause.
- Table name: Table used to fetch specified record from table using limit clause.
- Asterisk (*): Asterisk used to select all columns from the table to fetch data.
- Limit N: Limit clause in PostgreSQL to select a specified number of rows from the table.
- Offset N: Offset clause used with limit clause fetch specified rows using offset value.
- Order by: Order by clause used in limit clause to fetch record in ascending or descending order.
- ASC: Fetch data in ascending order by using order by and limit clause in PostgreSQL.
- DESC: Fetch data in descending order by using order by and limit clause in PostgreSQL.
How LIMIT clause works in PostgreSQL?
- This clause is an optional clause for select statement.
- Limit clause is very important in PostgreSQL.
- We can use the limit clause by using the offset clause. Offset clause will skip the N number of rows before returning the result.
- Limit is used to limit the number of records return from the table.
- Limit is an optional clause of PostgreSQL select statement that is used to fetch limited no of rows from the whole table.
- This clause is also used with an offset clause to fetch records from the table.
- We can use this clause with an order by clause to find ascending and descending numbers.
- Using limit in order by clause we can easily find the top and bottom rows of the table.
- Limit clause returns no of rows from the table which was mentioned in limit value at the time of fetching record from table.
Examples of PostgreSQL LIMIT
Given below are the examples of PostgreSQL LIMIT:
We have used an employee table to describe an example of a limit in PostgreSQL:
Example #1
Employee table to describe example of limit in PostgreSQL.
Code:
select * from employee;
Output:
Example #2
Example of limit by fetching data of all columns and specified number of rows from the table.
In the below example, we are fetching records from all columns and retrieving data only from three columns using limit in PostgreSQL.
Code:
select * from employee limit 3;
Output:
Example #3
Example of limit by fetching data of specified column and specified number of rows from the table.
In the below example, we are fetching records from specified columns and retrieving data only from four columns using limit in PostgreSQL.
Code:
select emp_id, emp_name, emp_address emp_salary from employee limit 4;
Output:
Example #4
Limit clause by using offset clause to fetch data from all columns and specified rows.
- In the below example, we are retrieving data from all columns and specified rows by using the limit and offset clause. Offset clause will skip the rows of N offset number.
- In the below example we are skipping three rows are as follows.
Code:
select * from employee limit 3 offset 3;
Output:
Example #5
Limit clause by using the offset clause to fetch data from the specified column and specified rows.
- In the below example, we are retrieving data from the specified column and specified rows by using the limit and offset clause.
- In the below example we are skipping three rows are as follows.
Code:
select emp_id, emp_name, emp_address emp_salary from employee limit 4 offset 3;
Output:
Example #6
Limit using order by clause.
1. Fetch the data in ascending order by using order by.
Code:
select emp_id, emp_name, emp_address emp_salary from employee order by emp_id ASC limit 4 offset 3;
Output:
2. Fetch the data in descending order by using order by.
Code:
select emp_id, emp_name, emp_address emp_salary from employee order by emp_id DESC limit 4 offset 3;
Output:
Conclusion
PostgreSQL limit clause is very important in PostgreSQL to return a limited number of rows from the select queries. We have used a limit clause using offset in PostgreSQL, also we have to fetch data in ascending and descending order, by using order by clause. It is an optional clause of select statement.
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This is a guide to PostgreSQL LIMIT. Here we discuss the introduction, how LIMIT clause works in PostgreSQL? and examples. You may also have a look at the following articles to learn more –
