How to write a condition that is always true?

Question

SQL

I make a selection of rows according to several conditions - sale or purchase (expressed as bool in the table), price (if it is not more than the specified one), quantity (also not more than the user-specified one). This results in a request like this:

SELECT * FROM products WHERE (bay=1) AND (price <= 5500) AND (quantity <= 3);

But there is one problem - the user may not filter rows by one or more parameters. For example, for such a case, you can write a negative number for the price, it naturally cannot be such, but this condition is absolutely not universal, but at least for bool.

Answer 1

AND 1=1

Answer 2

If I understand your problem correctly, you just need to construct a query depending on the passed values. Those. if the user has not specified a filter, then such an AND condition should not be present in the query either. For a PL not specified by you, there should be some SQL Builder that is conveniently suitable for solving such a problem.

Answer 3

For a more advanced filtering in the form of a set of something - you should think about a stored procedure, which, for example, will receive a bunch of filter parameters
, and in it, in the simple case, it is already uniform
where
param1 is null or filed1=param1
...
and paramN is null or filedN=paramN
of course, the parameter can be some kind of enum-like one that will drag a bunch of preliminary requests / calculations (for example, only goods that were sold to other customers from the same group, etc.)