Detailed explanation of data types of MySQL columns

Detailed explanation of the data type of the column

Numerical type

• tinyint Very small data 1 Bytes
• smallint Smaller data 2 Bytes
• mediumint Medium data 3 Bytes
• int Standard integer 4 Bytes
• bigint Big data 8 Bytes
• float Floating point numbers 4 Bytes
• double Floating point numbers 8 Bytes （ There's a problem with accuracy ）
• decimal Floating point numbers in string form In financial calculation , Generally used decimal

character string

• char String of fixed size 0-255
• varchar Variable string 0-65535 Common variables string
• tinytext Micro text 2^8-1
• text Text string 2^16-1 Save large text

Time date

• data YYYY-MM-DD Date format
• time HH:mm：ss Time format
• datatime：YYYY-MM-DD HH:mm：ss The most common time format
• timestamp Time stamp 1970.1.1 The number of milliseconds up to now Also more commonly used
• year The year means

null

• No value , Unknown
• – Be careful , Do not use null Carry out operations , The result is null