SQL Data Types

SQL Data Types

Each column in a table must have a data type. The data type indicates the type of value that is stored within the column.

Each database can accept different data types, but in general, the list of data types are:

Strings Types

Data typeDescription
CHAR(n)Character string. Fixed-length n. Minimal length is 1. If you assign a value to a CHAR column containing fewer characters than the defined length, the remaining space is filled with blanks characters.
VARCHAR(n)Character string. Variable length. Maximum length n. Minimal length is 1
BINARY(n)Binary string. Fixed-length n
VARBINARY(n) or BINARY VARYING(n)Binary string. Variable length. Maximum length n

Numerics Types

Data typeDescription
INTEGERInteger numerical. From -2,147,483,648 to 2,147,483,647.
SMALLINTInteger numerical. From -32,768 to 32,767
BIGINTInteger numerical. From -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
DECIMAL(p,s) or NUMERIC(p,s)Exact numerical, precision p, scale s. Precision is the maximum total number of decimal digits that will be stored, both to the left and to the right of the decimal point. Scale is the number of decimal digits that will be stored to the right of the decimal point. This number is subtracted from p to determine the maximum number of digits to the left of the decimal point. Example: decimal(5,2) is a number that has 3 digits before the decimal and 2 digits after the decimal.
FLOAT(p)Approximate numerical, mantissa precision p. A floating number in base 10 exponential notation. The size argument for this type consists of a single number specifying the minimum precision
REALApproximate numerical, mantissa precision 7
FLOATApproximate numerical, mantissa precision 16
DOUBLE PRECISIONApproximate numerical, mantissa precision 16

Date and Time Types

Data typeDescription
DATEStores year, month, and day values
TIMEStores hour, minute, and second values
DATETIMEStores year, month, day, hour, minute, and second values
TIMESTAMPStores the number of seconds since the Unix epoch
TIME WITH TIME ZONEStores time of day with time zone
TIMESTAMP WITH TIME ZONEStores timestamp with time zone

Other Data Types

Data typeDescription
BOOLEANStores TRUE or FALSE values
ARRAYA set-length and ordered collection of elements
MULTISETA variable-length and unordered collection of elements
XMLStores XML data

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