A data type reference table. If you're designing a database then you don't need me to tell you what this is.
My personal opinion is to always try to use the minimal type and length of the value required. For example, a comment of 500 words should only be TEXT (~64Kb) rather than LONGTEXT (~4Gb).
| Data Type | Column Type | Range or Description | Storage |
| Numeric | TinyInt | Signed values from -128 to 127 | 1 byte |
| Unsigned values from 0 to 255 | |||
| Numeric | SmallInt | Signed values from -32768 to 32767 | 2 bytes |
| Unsigned values from 0 to 65535 | |||
| Numeric | MediumInt | Signed values from -8388608 to 8388607 | 3 bytes |
| Unsigned values from 0 to 16777215 | |||
| Numeric | Int | Signed values from -2147683648 to 2147483647 | 4 bytes |
| Unsigned values from 0 to 4294967295 | |||
| Numeric | BigInt | Signed values from -9223372036854775808 to 9223372036854775807 | 8 bytes |
| Unsigned values from 0 to 18446744073709551615 | |||
| Numeric | Float | Minimum non-zero values: 1.175494351E-38 | 4 bytes |
| Maximum non-zero values: 3.402823466E+38 | |||
| Numeric | Double Float | Minimum non-zero values: 2.2250738585072014E-308 | 8 bytes |
| Maximum non-zero values: 1.7976931348623157E+308 | |||
| Numeric | Decimal | Varies | Maximum width + 2 bytes |
| String | Char | Range 1-255 characters | Always filled max width |
| String | VarChar | Range 1-255 characters | Length of string + 1 byte |
| String | TinyBlob, TinyText | Max length 255 characters | Length of string + 1 byte |
| String | Blob, Text | Max length 65535 characters (~64KB of text) | Length of string + 2 bytes |
| String | MediumBlob, MediumText | Max length 16777216 characters (16MB of text) | Length of string + 3 bytes |
| String | LongBlob, LongText | Max length 4294967295 characters (4GB of text) | Length of string + 4 bytes |
| String | Enum ('value','value2',...) | String object that can have only one set of allowed values | 1 or 2 bytes |
| String | Set ('value','value2',...) | String object that can have one or many values of a set of allowed values. | 1, 2, 3, 4, or 8 bytes |
| Date/Time | Date | 'YY-MM-DD', 'YYYY-MM-DD', 'YYMMDD' | 3 bytes |
| Range "1000-01-01" to "9999-12-31" | |||
| Date/Time | Time | 'HH:MM:SS', 'HHMMSS', 'HHMM', 'HH' | 3 bytes |
| Range "-838:59:59" to "838:59:59" | |||
| Date/Time | DateTime | 'YYYY-MM-DD HH:MM:SS' | 8 bytes |
| "0000-01-01 00:00:00" to "9999-12-31 23:59:59" | |||
| Date/Time | TimeStamp | 19700101000000 to sometime in the year 2037 | 4 bytes |
| Date/Time | Year | 'YYYY', 'YY' Range "1901" to "2155" | 1 byte |
