My sql Select query where condition is not working properly

Question

I have two tables sale and receipt ,table structure is give below.

sale table

id   total sale_type     cust_id

1    100    credit         10

2    200    payment        9

receipt

id  net_mount   payment_type  cust_id

1    50         CDM           10

2    150       Hand Over       9

My problem is when i give sale_type in where condition i got matched data from sale table and also the data from receipt table, when sale_type is give i want only the matched value of sale table . same situation in the case of payment_type.

Code

 <?php
 $where='where 1';
 $where2='where 1';
if($sale_type<>'')
 {
  $where.=" and sale.sale_type='$sale_type'";

 } 
 if($deposited_type<>'')
 {
 $where2.=" and receipt.deposited_type='$deposited_type'";

}

if($cust_name<>'' || $cust_id<>'')
              {
            $where.=" and (sale.cust_id='$cust_name' or sale.cust_id='$cust_id')";
           $where2.=" and (receipt.cust_id='$cust_name' 
           or receipt.cust_id='$cust_id')";
              }

select total, net_amount from (select total, null as net_amount,
2 as sort_col from    sale  $where union
all select  
null as total, net_amount, 1 as sort_col from receipt $where2)
as a order by  sort_col desc
?>

Any body give any solution for these issue?

Answer 1

The FROM part of your query has to be parametrized in function of the tables you need. You have to do something like this:

<?php
$where='where 1';
$where2='where 1';
if ($sale_type<>'' && $deposited_type<>'') {
    $where.=" and sale.sale_type='$sale_type'";
    $where2.=" and receipt.deposited_type='$deposited_type'";
    $tables = "sales INNER JOIN receipt ON sales.cust_id. = receipt.cust_id"
} 
else if($sale_type<>'') {
    $where.=" and sale.sale_type='$sale_type'";
    $tables = "sales"
}
else if($deposited_type<>'') {
  $where2.=" and receipt.deposited_type='$deposited_type'";
  $tables = "receipt"
 }

and then you build your query with:

SELECT ...
FROM $tables
WHERE conditions with $where and $where2

Beware of SQL injections with conditions like receipt.deposited_type='$deposited_type'

Answer 2

I think your database structure is wrong, if the customer made a more than one sale the query will generate a duplicate result

Please create a database structure like below

    sale(id,total,sale_type,cust_id)
    receipt(id,net_mount,payment_type,sale_id)

In the above table you can put sale_id in receipt table instead of cust_id

so the query will be

 select sale.total,receipt.net_amount,receipt.payment_type from sale INNER JOIN 
 receipt ON sale.id=receipt.sale_id where sale.sale_type='credit'

You can easily generate above query in php. Please let me for further clarification.