Chapter 11. Data Types
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Chapter 11. Data Types

Table of Contents

11.1. Data Type Overview

11.1.1. Numeric Type Overview
11.1.2. Date and Time Type Overview
11.1.3. String Type Overview

11.2. Numeric Types

11.2.1. Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT
11.2.2. Fixed-Point Types (Exact Value) - DECIMAL, NUMERIC
11.2.3. Floating-Point Types (Approximate Value) - FLOAT, DOUBLE
11.2.4. Bit-Value Type - BIT
11.2.5. Numeric Type Attributes
11.2.6. Out-of-Range and Overflow Handling

11.3. Date and Time Types

11.3.1. The DATE, DATETIME, and TIMESTAMP Types
11.3.2. The TIME Type
11.3.3. The YEAR Type
11.3.4. YEAR(2) Limitations and Migrating to YEAR(4)
11.3.5. Automatic Initialization and Updating for TIMESTAMP and DATETIME
11.3.6. Fractional Seconds in Time Values
11.3.7. Conversion Between Date and Time Types
11.3.8. Two-Digit Years in Dates

11.4. String Types

11.4.1. The CHAR and VARCHAR Types
11.4.2. The BINARY and VARBINARY Types
11.4.3. The BLOB andTEXT Types
11.4.4. The ENUM Type
11.4.5. The SET Type

11.5. Data Type Default Values

11.6. Data Type Storage Requirements

11.7. Choosing the Right Type for a Column

11.8. Using Data Types from Other Database Engines

MySQL supports a number of SQL data types in several categories: numeric types, date and time types, and string (character and byte) types. This chapter provides an overview of these data types, 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 permissible formats in which you can specify values.

MySQL also supports extensions for handling spatial data. For information about these data types, see Section 12.18, "Spatial Extensions".

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 (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.

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