如何根据一个或多个条件从表中选择数据？

Question

I am working using MySQL/PHP, I wanted to select data from a table based on one or more condition but using minimum if statements. For example if I have a table

Students | Register | End    | Points
Mark     | 14/1     | 18/6   | 14 
Dina     | 18/12    | 19/2   | 1 
Karl     | 1/1      | 1/2    | 9 

I have a form where user can look for data based on one or more criteria (register, end, points) based on the data he chose to set.

If he only set one of the criteria lets say after an date, he will get all results based on that date.

If he set two or three conditions maybe (register and end) or (end and points) or even (register and end and points) he will get the result based on all conditions joint together not only one of them or all of them separately.

when I use AND between conditions and the user don't set one of the conditions it returns empty query.

when I use OR between conditions and the user choose multiple conditions it returns data but based on each of conditions separately not joining it.

Queries I tried:

SELECT * FROM table WHERE Register >= '$choice1' OR End <= '$choice2' OR Points = '$choice3'; 

SELECT * FROM table WHERE Register >= '$choice1' AND End <= '$choice2' AND Points = '$choice3'; 

What is the best way to do that?

Answer 1

Use php to build your WHERE clause, something like this:

$condition = '';

if($choice1 != '')
  $condition .= "Register >= '$choice1'";

if($choice2 != '')
  $condition .= ($condition != '' ? " AND " : '') . "End <= '$choice2'";

if($choice3 != '')
  $condition .= ($condition != '' ? " AND " : '') . "Points = '$choice3'";

$sql = "SELECT * FROM table" .($condition != '' ? " WHERE $condition;" : ";");