Chapter 13 Data Types

Table of Contents

13.1 Numeric Data Types

13.1.1 Numeric Data Type Syntax

13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT

13.1.3 Fixed-Point Types (Exact Value) - DECIMAL, NUMERIC

13.1.4 Floating-Point Types (Approximate Value) - FLOAT, DOUBLE

13.1.5 Bit-Value Type - BIT

13.1.6 Numeric Type Attributes

13.1.7 Out-of-Range and Overflow Handling

13.2 Date and Time Data Types

13.2.1 Date and Time Data Type Syntax

13.2.2 The DATE, DATETIME, and TIMESTAMP Types

13.2.3 The TIME Type

13.2.4 The YEAR Type

13.2.5 Automatic Initialization and Updating for TIMESTAMP and DATETIME

13.2.6 Fractional Seconds in Time Values

13.2.7 What Calendar Is Used By MySQL?

13.2.8 Conversion Between Date and Time Types

13.2.9 2-Digit Years in Dates

13.3 String Data Types

13.3.1 String Data Type Syntax

13.3.2 The CHAR and VARCHAR Types

13.3.3 The BINARY and VARBINARY Types

13.3.4 The BLOB and TEXT Types

13.3.5 The ENUM Type

13.3.6 The SET Type

13.4 Spatial Data Types

13.4.1 Spatial Data Types

13.4.2 The OpenGIS Geometry Model

13.4.3 Supported Spatial Data Formats

13.4.4 Geometry Well-Formedness and Validity

13.4.5 Spatial Reference System Support

13.4.6 Creating Spatial Columns

13.4.7 Populating Spatial Columns

13.4.8 Fetching Spatial Data

13.4.9 Optimizing Spatial Analysis

13.4.10 Creating Spatial Indexes

13.4.11 Using Spatial Indexes

13.5 The JSON Data Type

13.6 Data Type Default Values

13.7 Data Type Storage Requirements

13.8 Choosing the Right Type for a Column

13.9 Using Data Types from Other Database Engines

MySQL supports SQL data types in several categories: numeric types, date and time types, string (character and byte) types, spatial types, and the JSON data type. This chapter provides an overview and more detailed description of the properties of the types in each category, and a summary of the data type storage requirements. The initial overviews are intentionally brief. Consult the more detailed descriptions for additional information about particular data types, such as the permissible formats in which you can specify values.

Data type descriptions use these conventions:

• For integer types, M indicates the maximum display width. For floating-point and fixed-point types, M is the total number of digits that can be stored (the precision). For string types, M is the maximum length. The maximum permissible value of M depends on the data type.

• D applies to floating-point and fixed-point types and indicates the number of digits following the decimal point (the scale). The maximum possible value is 30, but should be no greater than M−2.

• fsp applies to the TIME, DATETIME, and TIMESTAMP types and represents fractional seconds precision; that is, the number of digits following the decimal point for fractional parts of seconds. The fsp value, if given, must be in the range 0 to 6. A value of 0 signifies that there is no fractional part. If omitted, the default precision is 0. (This differs from the standard SQL default of 6, for compatibility with previous MySQL versions.)

• Square brackets ([ and ]) indicate optional parts of type definitions.