Syntax:
ELT(N,str1,str2,str3,...)

ELT() returns the Nth element of the list of strings: str1 if N = 1,
str2 if N = 2, and so on. Returns NULL if N is less than 1, greater
than the number of arguments, or NULL. ELT() is the complement of
FIELD().

URL: https://dev.mysql.com/doc/refman/8.0/en/string-functions.html

