Microsoft SQL Server/Variables
Declaration and affectation Edit
Every variable name begins with an at.
- Integer operations:
declare @i int
set @i = 5
declare @j int
set @j = 6
print @i+@j -- displays 11
- Character operations:
declare @k char
set @k = '5'
declare @l char
set @l = '6'
print @k+@l -- displays 56
Types Edit
The possible variable types are similar to the table fields ones[1]:
Characters Edit
Those beginning by "n" are in Unicode format.
char, nchar, nvarchar, ntext, text, varchar.
To save a few memory space, it's possible to set a characters number limit during the declaration:
varchar(255)
The variable of characters maximum size is 2 GB[2] :
varchar(MAX)
Numbers Edit
decimal, int (tinyint, smallint, bigint), float, money, numeric, real, smallmoney.
Dates Edit
date, datetime, datetime2, datetimeoffset, smalldatetime, time.
Personalized types Edit
In addition to the native types, it's possible to create one's own data types with CREATE TYPE.
Type determination Edit
The function SQL_VARIANT_PROPERTY returns a given field type[3]. Example:
SELECT SQL_VARIANT_PROPERTY(Field1, 'BaseType')
FROM table1