SQL convert varchar column to float

Question

An importing tool put every column in several tables as varchar(max) and I am looking for the fastest way to convert the columns to the proper type.

This works fine,

Answer 1

Are the decimal separator of the system configured the same way as content from varchar field? In your case i will advice you to créate a new column(FLOAT) instead of alter existing column. Then fill that field with an update.

Here is a way to explicit convert text to float. IN SQL Server this query :

select cast(replace('12,5',',','.') as float)*2

Resutns 25 as response. That means is converted successfull to FLOAT

So to fill you new col with casted values you could do:

UPDATE Table SET FloatField=CAST(REPLACE(TextField,',','.') AS FLOAT)

That replace the , for . (In case there is any) and then converts to FLOAT. Hope this help.