How can you query a column for any value in that column? (ie. How do I build a dynamic where clause that can either filter the value, or not.)
I want to be able to query for either a specific value, or not. For instance, I might want the value to be 1, but I might want it to be any number.
Is there a way to use a wild card (like "*"), to match any value, so that it can be dynamically inserted where I want no filter?
select int_col from table where int_col = 1 // Query for a specific value
select int_col from table where int_col = * // Query for any value
The reason why I do not want to use 2 separate SQL statements is because I am using this as a SQL Data Source, which can only have 1 select statement.
Sometimes I would query for actual value (like 1, 2...) so I can't not have a condition either.
I take it you want some dynamic behavior on your
WHERE clause, without having to dynamically build your
With a single parameter, you can use
COALESCE) like this:
SELECT * FROM Table WHERE ID = ISNULL(@id, ID)
which allows a
NULL parameter to match all. Some prefer the longer but more explicit:
SELECT * FROM Table WHERE (@id IS NULL) OR (ID = @id)
A simple answer would be use: IS NOT NULL. But if you are asking for say 123* for numbers like 123456 or 1234 or 1237 then the you could convert it to a varchar and then test against using standard wild cards.
In your where clause:
cast(myIntColumn as varchar(15)) like '123%'.
Assuming the value you're filtering on is a parameter in a stored procedure, or contained in a variable called
@Value, you can do it like this:
select * from table where @Value is null or intCol = @Value
@Value is null then the
or part of the clause is ignored, so the query won't filter on intCol.
I don't quite understand what you're asking. I think you should use two different queries for the different situations you have.
When you're not looking for a specific value:
SELECT * FROM table
When you are looking for a specific value:
SELECT * FROM table WHERE intcol = 1
You can use the parameter as a wildcard by assigning special meaning to NULL:
DECLARE @q INT = 1 SELECT * FROM table WHERE IntegerColumn = @q OR @q IS NULL
This way, when you pass in NULL; you get all rows.
If NULL is a valid value to query for, then you need to use two parameters.
If you really want the value of your column for all rows on the table you can simply use
select int_col from table
If you want to know all the distinct values, but don't care how many times they're repeated you can use
select distinct int_col from table
And if you want to know all the distinct values and how many times they each appear, use
select int_col, count(*) from table group by int_col
To have the values sorted properly you can add
order by int_col
to all the queries above.
Share and enjoy.
The equivalent of wildcards for numbers are the comparators.
So, if you wanted to find all positive integers:
select int_col from table where int_col > 0
any numbers between a hundred and a thousand:
select int_col from table where int_col BETWEEN 100 AND 1000
and so on.