SQL: Common Data Types in SQL Server

Here is a table of the most commonly used data types in SQL Server

Data TypeDescription
Char()Fixed length string, unused spaces get padded and eat up memory: size 0-255
Varchar()Variable length string, unused spaces don’t use memory: 8000 chars
Nvarchar()Designed to handle Uni Code data (UFT-8): 4000 chars
nvarchar(max)536-870-912 characters
TextUp to 2GB of text data
Identity(x,y)Auto incrementing number with x being starting point and y = steps, so Identity(1,1) starts and1 and counts by 1
INTinteger (whole number, no decimals)
Decimal(x,d)floating point decimal number, x is size, d is number of places after the decimal
float(n)floating precision number, Float(24) = 4-bytes, Float(53) = 8-bytes — float(53) is default
Bool or BooleanBinary choice, 0 = False and 1 = True
DateDate data type “YYYY-MM-DD” (if set to US settings)
DATETIMEdatetime data type “YYYY-MM-DD HH:MM:SS” (if set to US settings)
YEARyear in for digit representation (ex 1908,1965,2011)

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