Mysql Numeric type conversion function

1. convert int to varchar often using concat function, such as concat (8, ' 0 ') to get string ' 80 '

and menu_name like CONCAT (CONCAT ('% ', #{pd.keywords}), '% ')

2. Convert varchar to int with cast (a as signed) a as varchar type string
Summary: Type conversions are like SQL Server, where type parameters are slightly different: CAST (xxx as type), convert (XXX, type)
Types of available
Binary , with binary prefix effect: binary
character type, with parameters: CHAR ()
Date: date
Time:
DateTime Date/Time type
floating point number: DECIMAL
integer: Signed
unsigned integer: UNSIGNED

SELECT * from Sys_menu where parent_id= ' 0 ' ORDER by cast (Menu_no as signed)

When Menu_no is a letter or kanji, the number converted is 0.

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Mysql Numeric type conversion function