[mysql] Error Code 1292 - Truncated incorrect DOUBLE value - Mysql

I've seen a couple cases where this error occurs:

1. using the not equals operator != in a where clause with a list of multiple or values

such as:

where columnName !=('A'||'B')

This can be resolved by using

where columnName not in ('A','B')

2. missing a comparison operator in an if() function:

select if(col1,col1,col2);

in order to select the value in col1 if it exists and otherwise show the value in col2...this throws the error; it can be resolved by using:

select if(col1!='',col1,col2);