SQLServer field type _ MySQL

First class: integer data bit: bit data type represents 0, 1 or NULL, that is, true, false. 1byte.int: 4 bytes are used to store positive and negative numbers. the storage range is-2 ^ 31 to 2 ^ 31-1.smallint. positive and negative values are stored in 2 bytes. storage range:-2 ^ 15 to 2 ^ 15-1tiny first class: integer data

Bit: the bit data type is 0, 1 or NULL, which indicates true or false. occupies 1 byte. int: stores positive and negative numbers in four bytes. the storage range is-2 ^ 31 to 2 ^ 31-1. smallint: stores positive and negative numbers in two bytes. storage range:-2 ^ 15 to 2 ^ 15-1 tinyint: the smallest integer type, only 1 byte, range: 0 so far ^ 8-1

Second Category: Exact value data

Numeric: The number can reach 38 bits. the number of bytes used for data storage varies with the number of bits used for data use. decimal: Similar to numeric.

Category 3: approximate floating point data

Float: uses 8 bytes to store data. A maximum of 53 characters can be entered. the range is-1.79E + 308 to 1.79E + 308. real: The number of digits is 24. The value ranges from-3.04E + 38 to 3.04E + 38.

Category 4: Date and time data

Datatime: The time range can be 1753/1/1 to 9999/12/31, and the time can be 3.33/1000 s. 8 bytes. smalldatetime: indicates that the time range can be from to 2079/12/31. 4 bytes.

Category 5: string data

Char: The length is set. the shortest is 1 byte and the longest is 8000 bytes. the length is left blank. varchar: The length is also set. the shortest value is 1 byte and the maximum value is 8000 bytes. the white space at the end is removed. text: the length and width are also set. up to 2 GB data can be stored.

Category 6: Unincode string data

Nchar: The length is set. the shortest is 1 byte and the longest is 4000 bytes. the length is left blank. it takes 2 bytes to store a character. nvarchar: the maximum length is 1 byte and 4000 bytes. the white space at the end is removed. it takes 2 bytes to store a character. ntext: The length is set. the shortest is 1 byte and the longest is 2 GB. the white space at the end is removed. it takes 2 bytes to store a character.

Category 7: currency data type

Money: The record amount range is-92233720368577.5808 to 92233720368577. 5807. 8 bytes are required. smallmoney: the record amount range is-214748.3648 to 214748. 36487. 4 bytes are required.

Category 8: Mark data

Timestamp: This data type is unique in each table! When a record changes in a table, the timestamp field of the record is automatically updated. uniqueidentifier: used to identify the unique record of many tables in the database.

Category 9: binary string data

Binary: a fixed-length binary string field. the minimum length is 1 and the maximum length is 8000. varbinary: when the tail of the data is 00, varbinary removes the image from it: a variable-length binary code string. The maximum length is 2 GB.