How to add multiple conditions in sql? - sql

Question

Here is my stored procedure:
ALTER PROCEDURE sp_searchedstudentrecords
(
#condition varchar(20),
#searchtext varchar(50),
#searchclass int
)
AS
begin
If (#condition = 'startswith')
select * from student where name like #searchtext+ '% '
else if (#condition = 'endswith')
select * from student where name like '%' +#searchtext
else
select * from student where name like '%' +#searchtext+ '%'
End
I have been added extra one text box for search by class with the above query.
#searchclass int
May i now what should be the query for search by class look like?
I'm new sql query and .net,
I have been created dropdown contains startswith,endswith and contains and one text box for search by name.
I already done select record where search by name, with this i need to select record from table where search by class.
Can anyone guide me for query?
Thanks,

Answer 1

Like this
select *
from student
where name like (case
when #condition = 'startswith' then #searchtext+ '% '
else
case when #condition = 'endswith' then '%' + #searchtext
else '%' + #searchtext + '%'
end
end)
and studentid = isnull(#searchclass, studentid)
Above query to studentid has been extra search
If any id to search passing value other wise pass null
This query should be given result.

Answer 2

As already suggested, it is better to do this in your front-end by constructing a parameterized query as described here. Since you cannot use the protective power of parameterized with LIKE, you must be careful to sanitize your string (avoid Sql injection).
When implementing in .NET, it is best practice to avoid string comparisons. You can define your filters as a fixed list of id->name pairs.
enum LikeFilterType
{
Startswith = 1,
Endswith = 2,
Inside = 3
// maybe exactly can be added later
}
IList<SelectListItem> FilterOptions = new List<SelectListItem>()
{
new SelectListItem() { Value = (int) LikeFilterType.Startswith, Text = "Starts with" },
new SelectListItem() { Value = (int) LikeFilterType.Endswith , Text = "Ends with" },
new SelectListItem() { Value = (int) LikeFilterType.Inside, Text = "Inside" }
}
Your combo may "bind" directly to this list and use selected value, not the string in your logic (what you display may change over time, you do not want to change logic when changing a displayed name!)
Coding in ASP.NET allows to have a more readable and maintainable code.
NOTE: keep in mind that user should know or will be affected by LIKE special characters.

Answer 3

I assuming your parameters are nullable, therefore you can just do like this
SELECT * FROM student
WHERE name LIKE ( CASE WHEN #condition = 'startswith' THEN #searchtext + '%'
WHEN #condition = 'endswith' THEN '%'+#searchtext
ELSE '%'+#searchtext+'%'
END
) AND
(#searchclass IS NULL OR studentClass = #searchclass)
#searchclass IS NULL is for you to check is the parameter's value and it wont clash even if your #searchclass is NULL
Hope it help ya.

Answer 4

Refer below updated stored procedure with Class filter.
Change Class column based on exact column name:
ALTER PROCEDURE sp_searchedstudentrecords
(
#condition varchar(20),
#searchtext varchar(50),
#searchclass int
)
AS
BEGIN
IF (#condition = 'startswith')
SELECT * FROM student WHERE name like #searchtext+ '% ' AND Class = #searchclass
ELSE IF (#condition = 'endswith')
SELECT * FROM student WHERE name like '%' +#searchtext AND Class = #searchclass
ELSE
SELECT * FROM student WHERE name like '%' +#searchtext+ '%' AND Class = #searchclass
END