Declare SQL: Description. Transact-sql

Today, almost every modern programmer knows what Transact-SQL is. This is the extension that is used in SQL Server. This development is tightly integrated into the Microsoft SQL language and adds programming constructors that are not initially provided in the databases. T-SQL supports variables, as in most other designs. However, this extension restricts the use of variables in ways that are not common in other environments.

Declaring Variables in DECLARE SQL

T-SQL uses the DECLARE statement (<var_name>) to declare a variable. For example, in the case of declaring the variable i as an integer using this operator, the command would look like this: DECLARE @i int.

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DECLARE @mytable table

col1 int NOT NULL

INSERT INTO @mytable VALUES (1)

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col1 int NOT NULL

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Support for local variables in SQL procedures allows you to assign and retrieve data values ​​in support of procedure logic. Variables in procedures are defined using the DECLARE SQL statement. Values ​​can be assigned to variables using the SET statement or as the default value when declaring a variable. Literals, expressions, query results, and special register values ​​can be assigned variables.

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