How To Convert Binary Strings into Integers in SQL Server Transact-SQL?

Binary strings and integers are convertible implicitly and explicitly. But there several rules you need to remember:

• Binary strings will be implicitly converted into an integer data type, if it is involved in an arithmetical operation with another integer data type operand.
• Binary strings will be implicitly converted into an integer data type, if it is assigned to a variable, a column or a parameter of an integer data type.
• Binary strings will be explicitly converted into integer data types using CAST() and CONVERT() functions.
• When converting binary strings that have more bytes than the target data type size, bytes on the left hand side will be truncated.
• When converting binary strings that have less bytes than the target data type size, 0x00 will be padded on the left hand side.

Examples showing in the tutorial exercise below will help you remembering those rules.

SELECT 0x66 + 44
GO
146

DECLARE @integer INT;
SET @integer = 0x66;
SELECT @integer + 44
GO
146

SELECT CAST(0x66 AS INT) + 44
GO
146

SELECT CONVERT(INT, 0x66) + 44
GO
146

-- Only last 4 bytes are used for INT conversion
SELECT 0x7700000066 + 44
GO
146

-- 8 bytes will be used for BIGINT conversion
SELECT 0x7700000066 + CONVERT(BIGINT,44)
GO
511101108370

-- 0x00 padded on the left hand side
SELECT 0x66 + 44
SELECT 0x00000066 + 44
GO
146
146

⇒Character Strings and Binary Strings in SQL Server Transact-SQL

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