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Chapter 10. Data Types

Table of Contents     [+/-]

10.1. Data Type Overview     [+/-]
10.2. Numeric Types
10.3. Date and Time Types     [+/-]
10.4. String Types     [+/-]
10.5. Data Type Storage Requirements
10.6. Choosing the Right Type for a Column
10.7. Using Data Types from Other Database Engines

MySQL supports a number of data types in several categories: numeric types, date and time types, and string (character) types. This chapter first gives an overview of these data types, and then provides a more detailed description of the properties of the types in each category, and a summary of the data type storage requirements. The initial overview is intentionally brief. The more detailed descriptions later in the chapter should be consulted for additional information about particular data types, such as the allowable formats in which you can specify values.

MySQL 4.1 and up also supports extensions for handing spatial data. Chapter 16, Spatial Extensions, provides information about these data types.

Data type descriptions use these conventions:

  • M indicates the maximum display width for integer types. For floating-point and fixed-point types, M is the total number of digits that can be stored. For string types, M is the maximum length. The maximum allowable 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 maximum possible value is 30, but should be no greater than M–2.

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