RAISERROR in SQL server

RAISERROR is used to generate custom error messages in SQL Server with a specified severity and state, commonly used for validations and business rule enforcement.

RAISERROR is used to raise a custom error message in SQL Server and optionally we can stop execution or roll back a transaction or log the error or return an error to the application.  It is commonly used in stored procedures, triggers, validations, and business rules.

Syntex

RAISERROR (message, severity, state)

Severity Levels

Severity	Meaning
0–10	Informational
11-16	User-defined errors (most common)
17-19	Software / resource errors
20-25	Fatal (connection terminated)

See the example. For the demo here we are creating.

CREATE TABLE Orders (     OrderID INT IDENTITY,     Amount  INT );

Now we are writing the business rule that Amount should be greater than 0 , if someone insert less than 0 data will into inserted and throw an error message.

DECLARE @Amount INT = -500; IF @Amount <= 0 BEGIN     RAISERROR ('Order amount must be greater than zero.', 16, 1);     RETURN; END INSERT INTO Orders (Amount) VALUES (@Amount);

Here we are trying to insert amount less than 0. Let’s run this

 

Now inserting amount greater than 0.

DECLARE @Amount INT = 500; IF @Amount <= 0 BEGIN     RAISERROR ('Order amount must be greater than zero.', 16, 1);     RETURN; END INSERT INTO Orders (Amount) VALUES (@Amount);

Data inserted successfully.

In this way we throe an error.