More delicate search capabilities...or advanced search that is!

Question

First, my personal header for most messages I post here:
"I am not a programmer, I know little about sql programming but I´m passionate about it, so I can learn if explained patiently".
And now to the message:
There´s a table. It´s called "tasks". Now, there´s a search field in which I can typically search in any field of that table. But here´s the thing: my users need to perform more specific searches, meaning advanced ones.
I have created a page with my top 10 forms refering to the 10 most common attributes my users like to filter by, such as: task responsible, due date, status, etc. Each field in this form has a value of course (PX_ID, PX_Status, etc). It has a "go" button and that´s it!
I realised I have to write a query from scratch if I want to use those variables to build a report, and here´s the thing: I managed to do it if, and only of my user completes every search field. When one of them is not completed the result is always "nothing". If the user completes only 1 field, and not the others...he sees nothing!
Of course this version of advanced search easy, just write down the conditions and you´re set! The thing is, and here´s where my knowledge of PL/SQL is not nearly enough to try to figure it out: how do I make this form work, regardless of what the user puts in any field? I mean: how do I make the search work with only the fields completed by the user, without caring that there might be fields empty?
I was tipped to "left join" and "if", but it beats me :)
Help pls?
Thanks!
Alejandro
And here comes the footer in case you didnt read the header:
"I am not a programmer, I know little about sql programming but I´m passionate about it, so I can learn if explained patiently".

Answer 1

Alejandro,
As one option...
If your table is called PEOPLE and has columns: first_name, surname, email_address etc.. and you have page items like PX_FIRST_NAME, PX_SURNAME, PX_EMAIL_ADDRESS where the user can type in what they want to search for, then your SQL query could be something like the following:
SELECT * FROM PERSONS
WHERE
(:PX_FIRST_NAME is null
OR
first_name like :PX_FIRST_NAME)
AND
(:PX_SURNAME is null
OR
SURNAME like :PX_SURNAME)
AND
(:PX_EMAIL_ADDRESS is null
OR
email_address like :PX_EMAIL_ADDRESS)
This way it will not matter if a user leaves one or more search criteria items empty.
Andy