04. MySQL Datatypes
Data types introduction
MySQL Data types
MySQL supports a number of SQL data types in several categories: numeric types, date and time types, string (character and byte) types.
Numeric types
MySQL supports all standard SQL numeric data types. These types include the exact numeric data types (INTEGER, SMALLINT, DECIMAL, and NUMERIC), as well as the approximate numeric data types (FLOAT, REAL, and DOUBLE PRECISION).
Integer Types
MySQL supports the SQL standard integer types INTEGER
(or INT) and SMALLINT
. As an extension to the standard, MySQL also supports the integer types TINYINT
, MEDIUMINT
, and BIGINT
.
Fixed-Point Types
The DECIMAL and NUMERIC types store exact numeric data values. These types are used when it is important to preserve exact precision, for example with monetary data. In MySQL, NUMERIC is implemented as DECIMAL, so the following remarks about DECIMAL apply equally to NUMERIC.
String types
The string types are CHAR, VARCHAR, BINARY, VARBINARY, BLOB, TEXT, ENUM, and SET. This section describes how these types work and how to use them in your queries.
Date time types
The date and time types for representing temporal values are DATE, TIME, DATETIME, TIMESTAMP, and YEAR. Each temporal type has a range of valid values, as well as a “zero” value that may be used when you specify an invalid value that MySQL cannot represent.
Question 1
SOLUTION:
4Question 2
SOLUTION:
- The length of a CHAR column is fixed to the length that you declare when you create the table.
- VARCHAR columns are variable-length strings.