Boolean Condition in PHP

Question

Hello I'm new to php and mySQL. Basically I have a table of users and I want to echo the id, name and surname of the users if their "valid" integer is equal to 1, here is my attempt;

<?php
$servername = "aaa";
$username = "aaa";
$password = "aaa";
$dbname = "aaa";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$sql = "SELECT ID, Name, Surname, Valid FROM myTable";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // output data of each row
while($row = $result->fetch_assoc()) {
        if($row["Valid"] = 1) {echo "id: " . $row["ID"]. " - Name: " . $row["Name"]. " " . $row["Surname"]. "<br>";
    }
}
} else {
echo "0 results";
}
$conn->close();
?>

Using this code gives me a list of all the users, even though their valid integers are zero.

Thanks,

Use strict comparison operator(`===`), like this: `if($row['Valid'] === 1){ ...` — Rajdeep Paul, Feb 02 '16 at 00:42
Dear @ern, Im just trying to learn the basics but I plan to use it similar to deleting a row. Rather than deleting it, I will change the valid bit to zero so that I can access the old information. — Kaan, Feb 02 '16 at 00:46
Then just `$row['Valid']` should work for you as an argument in your statement..Since 0 means false. — ern, Feb 02 '16 at 00:55

score 2 · Accepted Answer · answered Feb 02 '16 at 00:42

2

In PHP to check for conditions as you are you need the == operator instead of the = operator. All you are doing is setting all the valid columns to 1.

if($row["Valid"] == 1)

answered Feb 02 '16 at 00:42

cschaefer

126
7

fusion3k · Answer 2 · 2016-02-02T00:59:37.030

1

You have to add a WHERE condition to your query:

$sql = "SELECT ID, Name, Surname, Valid FROM myTable WHERE Valid=1";

If you query select all fields of table, you can also perform the query as:

$sql = "SELECT * FROM myTable WHERE Valid=1";

Edit:

As suggested by my dears and accurate censors in the comments below, if you use my suggested solution, the check of $row[Valid] in the while loop, although not invalidate the result, is totally unnecessary.

So - to obtain the list of users with field Valid = 1, you can write in this simple way:

while( $row = $result->fetch_assoc() )
{
    echo "id: " . $row["ID"]. " - Name: " . $row["Name"]. " " . $row["Surname"]. "<br>";
}

edited Feb 02 '16 at 00:59

answered Feb 02 '16 at 00:42

fusion3k

11,568
4
25
47

Though this certainly does make sense it does _not_ answer the question in a strict sense... – arkascha Feb 02 '16 at 00:43
1

where is not required for any queries. If where is excluded, it will match all rows. – Devon Bessemer Feb 02 '16 at 00:43
@arkascha yes, you are right – fusion3k Feb 02 '16 at 00:44
@Devon yes, I know! I have interpreted «I want to echo» as «I want to select». Please note that the result is anyway the same – fusion3k Feb 02 '16 at 00:48
then you'd need to tell the OP not to use their intended comparison in conjunction with your answer. They may not know what to do with your answer. – Funk Forty Niner Feb 02 '16 at 00:51
@Fred-ii- as commanded! – fusion3k Feb 02 '16 at 01:00

Boolean Condition in PHP

2 Answers2

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