Error converting data type varchar to float

Error converting data type varchar to float

Solution:
use isNumeric() to check if it's a numerical value. If it is, then continue checking next condition :)

Use the ISNUMERIC function to make sure the data is numeric before doing your comparison.

Be aware that 1e4 is a valid number in scientific notation as well as 1d2, etc.

select * from TT 
where ISNUMERIC(field_name)=1
AND CAST(field_name as float) > 2.5

isNull() is useful as well

isNull( field_name, '0' )