Skip to main content

Variables in T-SQL

Variables can be used to store the data in temporally based on data type.
Variable name begin with @ symbol.
There are two types of variables in T-SQL.
1. Local Variables (It must begin @ symbol).
2. Global Variables (it must begin @@ symbol) this variables also known as system variables.

Syntax Declare a Variable
DECLARE @Variable-Name DATATYPE

EXAMPLE:

DECLARE @Name VARCHAR(100)
In before 2008 versions of SQL SERVER we declare a variable and assign a value in 2 lines.
               
DECLARE @Name VARCHAR(100)
SET @Name='LeadFirstSQL'

In 2008 and Later versions of SQL SERVER we declare a variable and assign a value in single line.
DECLARE @Name VARCHAR(100) ='LeadFirstSQL'

Variables must be declare and used with the same batch.
DECLARE @Name VARCHAR(100) ='LeadFirstSQL'
SELECT @Name AS Nam
GO
SELECT @Name AS Name

If we are trying to execute above statement we get the error. Because of before the GO all the Queries are treated as single batch after the GO it treated as different batch.
Msg 137, Level 15, State 2, Line 1
Must declare the scalar variable "@Name".

We can also use variables as Table Valued Parameters.





  

Labels:

Comments

Post a Comment

Popular posts from this blog

How to Use Merge Statement Using XML Data

We now that merge statement in SQL SERVER. With Merge statement we can merge the data from Source table into Target table. In the Last article we have already seen about Merge Statement .   These articles we will work around merge statement over xml data type. We know that xml data type SQL SERVER. XML Data type is used to storing xml data used Bulk Insert Data into SQL Tables. Example: --Create Student Table if object_id ( 'Student' ) is null create table Student ( id int identity ( 1 , 1 ) , Name varchar ( 20 ), Marks int ) Declare Xml Data Type and Assign Some Xml Data. Declare @Data xml set @Data = '<Root> <Student> <Name>Rakesh</Name> <Marks>80</Marks> </Student> <Student> <Name>Mahesh</Name> <Marks>90</Marks> </Student> <Student> <Name>Gowtham</Name...
Post a Comment
Read more

Rank Functions in SQL SERVER

1 . ROW_NUMBER () OVER ( [PARTITION BY CLAUSE] < ORDER BY CLUASE >): Returns the sequantial number of a row within the a partition of result set at 1 for the first row of the each partition. 2. RANK () OVER ( [PARTITION BY CLAUSE] < ORDER BY CLUASE >): Returns rank for rows within the partition of result set. 3. DENSE_RANK () OVER ( [PARTITION BY CLAUSE] < ORDER BY CLUASE >): Returns rank for rows within the partition of result set.With out any gaps in the ranking. 4. NTILE ( INTEGER_EXPRESSION ) OVER ( [PARTITION BY CLAUSE] < ORDER BY CLUASE >): Distributes the rows in an ordered partition into a specified number of groups. Examples: --create Employee table create table Employee (                 EmpId int identity ( 1 , 1 ) primary key ,              ...
1 comment
Read more