How do I use a PHP variable inside $row["..."];

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Hello,
in the SQL SELECT, when we use $row["table name"], how can we use a PHP variable instead of string table name?

What I have tried:

<pre>
for ($i=1; $i <= 1000; $i++){
$sql ="SELECT * FROM SPC WHERE id='$i'";
$result = $con->query($sql);
$row = $result->fetch_assoc();
$panel = $row["Panel"];
}
//No problem to this point, I got what I wanted
//Now, can we make "Panel" as a PHP variable?, I tried this but it's not working
$prmetr = "Panel";
$panel = $row["<?php echo $prmetr; ?>"];
//or
$panel = $row['$prmetr'];
//not working too
<pre>

Posted 12-May-20 13:16pm

Member 14819235

Updated 13-May-20 7:05am

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phil.o · Accepted Answer · 2020-05-12T21:52:00

Try

PHP

$row[$prmetr]

You should also used a prepared statement instead of concatenating strings to build your query:
PHP MySQL Prepared Statements[^]

And the fact that you enclose the id between quotes suggests that you defined a numeric field in your database using a string type; this is also a bad practice, you always should use the proper datatype.

W∴ Balboos, *GHB* · Accepted Answer · 2020-05-13T07:06:00

Solution 2

You are going through a loop for all 1000 values of $id. That is incredibly wasteful of resources.

You'd get the same results with a single query something like:
SELECT * FROM SPC WHERE id BETWEEN 0 AND 1000 ORDER BY id
Then work with the results set in a loop.

Beyond that, as noted in solution 1, you should not have the quotes around your php variable value when it's used as an index.

Posted 13-May-20 7:06am

W∴ Balboos, GHB

Updated 13-May-20 7:07am

v2

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Member 14819235 14-May-20 11:38am

I will try it, thank you so much

W∴ Balboos, GHB 14-May-20 11:47am

As a free bonus help: if you are using an indexed data type, like your $row[], you need to wrap it in curly braces if it's within a double-quoted text string.

Like this: $text = "My name is {$row['name']}";