Mysql numeric type conversion function

1. Convert Int to varchar often concat functions are used, such as concat(8,'0') to get the string '80'
2. Convert varchar to Int with cast(a as signed) a as varchar string
Conclusion: the type conversion is like SQL Server1, that is, the type parameters are slightly different: CAST(xxx AS type), CONVERT(xxx type)
Available types
Base 2, with the binary prefix: BINARY
Character type, with parameter: CHAR()
Date: DATE
Time: TIME
Date time type: DATETIME
Floating point number: DECIMAL
Integer: SIGNED
Unsigned integer: UNSIGNED