Help Center/ GaussDB/ Compatibility(Distributed)/ MySQL Compatibility Description/ M-compatible Mode/ Data Types/ Numeric Data Types
Updated on 2025-08-22 GMT+08:00
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Numeric Data Types

Unless otherwise specified, the precision, scale, and number of digits cannot be set to floating-point values in M-compatible mode by default. You are advised to use valid integer values.

Table 1 Integer types

MySQL

GaussDB

Difference

BOOL

Supported, with differences.

Output format: The output of SELECT TRUE/FALSE in GaussDB is t or f, and that in MySQL is 1 or 0.

MySQL: The BOOL/BOOLEAN type is actually mapped to the TINYINT type.

BOOLEAN

Supported, with differences.

TINYINT[(M)] [UNSIGNED] [ZEROFILL]

Supported, with differences.
Input format:
  • MySQL:

    If a character string with multiple decimal points (such as "1.2.3.4.5") is entered, MySQL will misparse the character string in loose mode, throw a warning, and insert the character string into the table successfully. For example, after "1.2.3.4.5" is inserted into the table, the value is 12.

  • GaussDB:

    If a character string with multiple decimal points (such as "1.2.3.4.5") is entered in loose mode, the characters after the second decimal point are truncated as invalid characters, a warning is thrown, and the character string is inserted into the table successfully. For example, after "1.2.3.4.5" is inserted into the table, the value is 1. After "1.6.3.4.5" is inserted into the table, the value is 2.

SMALLINT[(M)] [UNSIGNED] [ZEROFILL]

Supported, with differences.

MEDIUMINT[(M)] [UNSIGNED] [ZEROFILL]

Supported, with differences.
MySQL requires 3 bytes to store MEDIUMINT data.
  • The signed range is –8388608 to +8388607.
  • The unsigned range is 0 to +16777215.
GaussDB is mapped to the INT type. Four bytes are required for storage. The value range is determined based on boundary values.
  • The signed range is –8388608 to +8388607.
  • The unsigned range is 0 to +16777215.

For other differences, see the description below the table.

INT[(M)] [UNSIGNED] [ZEROFILL]

Supported, with differences.
Input format:
  • MySQL:

    If a character string with multiple decimal points (such as "1.2.3.4.5") is entered, MySQL will misparse the character string in loose mode, throw a warning, and insert the character string into the table successfully. For example, after "1.2.3.4.5" is inserted into the table, the value is 12.

  • GaussDB:

    If a character string with multiple decimal points (such as "1.2.3.4.5") is entered in loose mode, the characters after the second decimal point are truncated as invalid characters, a warning is thrown, and the character string is inserted into the table successfully. For example, after "1.2.3.4.5" is inserted into the table, the value is 1. After "1.6.3.4.5" is inserted into the table, the value is 2.

INTEGER[(M)] [UNSIGNED] [ZEROFILL]

Supported, with differences.

BIGINT[(M)] [UNSIGNED] [ZEROFILL]

Supported, with differences.
Table 2 Arbitrary precision types

MySQL

GaussDB

Difference

DECIMAL[(M[,D])] [ZEROFILL]

Supported, with differences.

-

NUMERIC[(M[,D])] [ZEROFILL]

Supported, with differences.

DEC[(M[,D])] [ZEROFILL]

Supported, with differences.

FIXED[(M[,D])] [ZEROFILL]

Supported, with differences.
Table 3 Floating-point types

MySQL

GaussDB

Difference

FLOAT[(M,D)] [ZEROFILL]

Supported, with differences.

The FLOAT data type does not support partitioned tables with the key partitioning policy.

FLOAT(p) [ZEROFILL]

Supported, with differences.

The FLOAT data type does not support partitioned tables with the key partitioning policy.

DOUBLE[(M,D)] [ZEROFILL]

Supported, with differences.

The DOUBLE data type does not support partitioned tables with the key partitioning policy.

DOUBLE PRECISION[(M,D)] [ZEROFILL]

Supported, with differences.

The DOUBLE PRECISION data type does not support partitioned tables with the key partitioning policy.

REAL[(M,D)] [ZEROFILL]

Supported, with differences.

The REAL data type does not support partitioned tables with the key partitioning policy.
Parent topic: Data Types