SqlServer change the field type --varchar turn decimal

　　There is data in the field in a table, and the data in the case of all-digital, directly to the field of type varchar changed to decimal likely to prompt " Error decimal data type varchar converted to a " can change the first field type int and then change the field type in the decimal can be.

　　alter table  table alter column field name int  not null

　　alter table table alter column field names decimal  not null