Question

I have the following problem:
I have an SQL table which contains texts and numbers in one column. I created two views to handle the texts and the numbers.

If I select the views in whole, they work as expected, but if I add a where statement to the select statement, I get the following error:

Conversion failed when converting the varchar value 'Thomas' to data type int.

Can I somehow tell the server to apply for the inner view’s where statement before the outer select’s one?

Please use the following SQL code for reproducing the error:

create schema tst
go
create table tst.tbl(strValue varchar(10))
insert tst.tbl(strValue)
    values ('Thomas'), ('1991'), ('Reto'), ('21'), ('Strub')
go
create view tst.tblStr as
    select strValue
    from tst.tbl
    where isnumeric(strValue)=0
go
create view tst.tblInt as
    select cast(strValue as int) intValue
    from tst.tbl
    where isnumeric(strValue)=1

go

select * from tst.tblStr order by strValue --ok
select * from tst.tblInt order by intValue --ok

go

select * from tst.tblInt where intValue<100 --not ok

go

select * from tst.tbl where isnumeric(strValue)=1 and cast(strValue as int) < 100 --ok

go

drop view tst.tblInt
drop view tst.tblStr
drop table tst.tbl
drop schema tst

Answer 1

Use a “case when” for view tst.tblInt.

 create view tst.tblInt as
    select 
            case when isnumeric(strValue)=1 
                then cast(strValue as int)
                else 0 
            end  intValue

    from tst.tbl
    where isnumeric(strValue)=1