SQL common data types

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Data type defines the type of value stored in the column.

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SQL common data types

Each column in a database table requires a name and data type. Each column in a database table is required to have a name and a data type.

SQL developers must decide when creating a SQL table the type of data that each column in the table will store. A data type is a label that is a guide for SQL to understand what type of data each column is expected to store. It also identifies how SQL interacts with the stored data.

The following table lists the common data types in SQL:

Data type	Description
CHARACTER(n)	Character/String. Fixed length n.
VARCHAR(n) or CHARACTER VARYING(n)	character/string. Variable length. Maximum length n.
BINARY(n)	Binary string. Fixed length n.
BOOLEAN	Storing TRUE or FALSE value
VARBINARY(n) or BINARY VARYING(n)	Binary string. Variable length. Maximum length n.
INTEGER(p)	Integer value (no decimal point). Precision p.
SMALLINT	Integer value (no decimal point). Accuracy 5.
INTEGER	Integer value (no decimal point). Accuracy 10.
BIGINT	Integer value (no decimal point). Accuracy 19.
DECIMAL(p,s)	Exact value, precision p, number of decimal places s. For example: decimal(5,2) is a number with 3 digits before the decimal point and 2 digits after the decimal point.
NUMERIC(p,s)	Exact numerical value, precision p, number of decimal places s. (Same as DECIMAL)
FLOAT(p)	Approximate numerical value, mantissa precision p. A floating-point number in base 10 exponential notation. The size parameter of this type consists of a single number that specifies the minimum precision.
REAL	Approximate numerical value, mantissa precision 7.
FLOAT	Approximate numerical value, mantissa precision 16.
DOUBLE PRECISION	Approximate numerical value, mantissa precision 16.
DATE	Stores the value of year, month and day.
TIME	Stores the values ​​of hours, minutes, and seconds.
TIMESTAMP	Stores the value of year, month, day, hour, minute and second.
INTERVAL	consists of some integer fields, representing a period of time, depending on the type of interval.
ARRAY	A fixed-length ordered set of elements
MULTISET	A variable set of elements Unordered collection of length
XML	Storing XML data

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SQL Data Type Quick Reference Manual

However, different databases provide different options for data type definition.

The following table shows the common names of some data types on various database platforms:

Yes/NoBitByteN/ABooleanNumber (integer)IntNumberIntIntNumber (single)FloatNumberFloatNumericCurrencyMoneyN /AN/AMoneyN/ACharCharCharChar##string (variable)Memo (65k+)Varchar2binary objectVarbinary (<8K)RawTextVarbinary

Data Types	Access	SQLServer	Oracle	MySQL	PostgreSQL
##boolean
integer				Integer	Integer
float		Real
currency
string (fixed)
Text (<256)	Varchar	Varchar	Varchar	Varchar
OLE Object Memo	Binary (fixed up to 8K)	Image (<2GB) Long	Blob	Binary

	Note: In different databases, the same data type may have different The name. Even if the name is the same, the dimensions and other details may be different! Please always check the documentation!