Scalar operators are used for operations with scalar values. Transact-SQL supports numeric and Boolean operators as well as concatenation.
There are unary and binary arithmetic operators. Unary operators are + and – (as signs). Binary arithmetic operators are +, -, *, /, and %. (The first four binary operators have their respective mathematical meanings, whereas % is the modulo operator.)
Boolean operators have two different notations depending on whether they are applied to bit strings or to other data types. The operators NOT, AND, and OR are applied to all data types (except BIT). They are described in detail in Chapter 6.
The bitwise operators for manipulating bit strings are listed here, and Example 4.6 shows how they are used:
Example 4.6
~(1001001) = (0110110)
(11001001) | (10101101) = (11101101)
(11001001) & (10101101) = (10001001)
(11001001) A (10101101) = (01100100)
The concatenation operator + can be used to concatenate two character strings or bit strings.
Global Variables
Global variables are special system variables that can be used as if they were scalar constants. Transact-SQL supports many global variables, which have to be preceded by the prefix @@. The following table describes several global variables. (For the complete list of all global variables, see Microsoft Docs.)
Source: Petkovic Dusan (2020), Microsoft SQL Server 2019: A Beginner’s Guide, Seventh Edition-McGraw-Hill Education.