MariaDB is number function

Question: I am creating a View in MariaDB to  to streamline a recordset requested by an application. As part of the View - there is a requirement to create some CASE statements and check to assess whether the data is numeric. 

How can I create a function to check if the data is numeric?

Answer: MariaDB has plenty of Numeric functions -  which process Functions dealing with numerals, including ABS, CEIL, DIV, EXP, PI, SIN, etc - but you are looking for a function - which checks to see if some data is a number. 

MariaDB has good support for creating functions and using regular expressions to evaluate data. Here is an example of a function called "isnumber". The DETERMINISTIC keyword sets the function to to always return one result given a set of input parameters.

I won't go into a whole conversation about regular expressions - but MariaDB has support for regexp . From the MariaDB documentation "regexp performs a pattern match of a string expression expr against a pattern pat"

CREATE FUNCTION `isnumber`(val varchar(1024)) RETURNS tinyint(1)
DETERMINISTIC
return val regexp '^[0-9]+$'

To check the status of the function :

SHOW FUNCTION STATUS WHERE `name` = 'my_function'

Read more  on MariaDB

MariaDB Cheatsheet

MariaDB RLIKE condition