根据一个 select 语句中另一列的不同要求对一列求和多次？

Question

I want to sum the invoices based on the state column. But i dont want to do 50 select statements. and the amount of states I query could vary
My Table

|invoice|state|
| 123   | NY  |
| 241   | VA  |
| 533   | WA  |

Can I do something like this:

$sql="Select SUM(invoice) where state=NY as NY AND where state=VA as VA";
$stmt = $conn->prepare($sql);
$stmt->execute();
$stmt->bind_result($ny,$va);
$stmt->fetch();
echo $ny;
echo $va;
//result: 123 241

Any ideas would be great! Do I have to make a select statement that executes in a for loop for each state in the array? thanks!

Answer 1

You can use GROUP BY for get sum by state wise.
Like

Select state,SUM(invoice) as Total FROM table_name GROUP BY state  

It will give you SUM on invoices by state wise.
May be this will help you.

Answer 2

Maybe you were looking for something like this?

SELECT SUM(CASE WHEN state='NY' THEN Invoice ELSE 0 END) AS 'NY',
       SUM(CASE WHEN state='VA' THEN Invoice ELSE 0 END) AS 'VA',
       SUM(CASE WHEN state='WA' THEN Invoice ELSE 0 END) AS 'WA' 
FROM table_name;

This will give you result like:

+-----+-----+-----+
| NY  | VA  | WA  |
+-----+-----+-----+
| 123 | 241 | 533 |
+-----+-----+-----+

If this is not the result you are looking for, you can add more details to your question like your expected output etc.