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In the world of SQL (Structured Query Language), the DELETE statement is used to delete existing records in a table. It’s a powerful command, and as such comes with a certain amount of risk. Use it with care, or you might delete more data than you intend!
Syntax of DELETE Statement
An important thing to note about the DELETE statement is that it should generally be used with a WHERE clause to avoid deleting all data from the table. Here is the basic syntax:
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DELETE FROM table_name WHERE condition; |
Usage of the DELETE Statement
Now let us discuss how to use the DELETE statement with different examples:
Example 1: Deletion of a Single Record
Consider a table “Employees” with columns “ID”, “Name”, and “Email”. Suppose we want to delete the record of an employee where ID is 5. Our SQL command would look like this:
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DELETE FROM Employees WHERE ID = 5; |
Example 2: Deletion of Multiple Records
Suppose we want to delete all records where the Name is “John”. Our SQL command would be:
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DELETE FROM Employees WHERE Name = 'John'; |
Example 3: Delete All Records
Suppose we want to delete all the records from the Employees table. Our SQL command would be:
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DELETE FROM Employees; |
Conclusion
In conclusion, the DELETE statement is a simple, yet powerful, command in SQL. Like any power, it must be used responsibly. Always ensure you understand the command thoroughly before deleting any data.
Important reminder: Always make sure you have a backup of your data before executing the DELETE statement!
Hope this guide helps you understand the SQL DELETE statement.