Re: index cannot be used when passing 'int' to 'varchar'

[Rick James]

I have some of the answers...

WHERE int_col = '123abc' -- parses the string literal to get 123
WHERE int_col = 'abc' -- parses the string to get 0
To convert a string to an int, you can do 0+'literal' or 0+char_col
WHERE int_col = '1234' -- seems (in newer versions of MySQL) to be equivalent to
WHERE int_col = 1234

The troubling case you had was none of the above --
WHERE char_col = 1234