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SQL DELETE & TRUNCATE

In this tutorial, you will learn how to delete your rows from the database table using the SQL DELETE and TRUNCATE statements.

Syntax

The basic syntax of the DELETE statement to delete rows in a table, can be given with:

				
					DELETE
FROM table_name
WHERE condition
				
			

The basic syntax of the TRUNCATE statement to delete all rows in a table, can be given with:

				
					TRUNCATE TABLE table_name
				
			

Examples

To understand the DELETE and TRUNCATE statements in a better way, let’s look at the following customers and orders tables in our tutorial database:

Now, let’s check out some examples that demonstrate how it actually works.

We have the following task be to solve using SQL statements

Delete both new customers Anna and Max from our database

The following Query will returns all the rows from customers table.

				
					DELETE FROM customers
WHERE customer_id IN (6,7)
				
			

After executing the above query, you’ll get the result set something like this:

Delete all customers from our database

As you can see the output contains everything the whole customers tables including all rows and columns.

				
					DELETE FROM customers
				
			
				
					TRUNCATE customers
				
			

Let’s say we are only interested in getting only specific columns from a table, then we could use the following  syntax of the SELECT statement:

Remove ALL customers from database

The following Query will returns all the rows from customers table.

				
					TRUNCATE TABLE customers
				
			

SELECT * helps you to examine the content of table that you are not familiar with. But be careful using it specially with big tables because database will retrieve everything which costs a lot of data movement across the network and might slow down the application

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