PHP variable question

Question

This works:

$customerBox = mysql_query("MY SQL STATEMENT HERE");  
$boxRow = mysql_fetch_array($customerBox);  

$customerBox = mysql_query("MY SQL STATEMENT AGAIN");
while($item = mysql_fetch_assoc($customerBox)) {
      foreach ($item as $columnName => $value) {
          if (empty($value)) {
               print $columnName;
          }
      }
}

This does not:

$customerBox = mysql_query("MY SQL STATEMENT HERE");  
$boxRow = mysql_fetch_array($customerBox);  

while($item = mysql_fetch_assoc($customerBox)) {
      foreach ($item as $columnName => $value) {
          if (empty($value)) {
               print $columnName;
          }
      }
}

Why? I guess I don't understand how variables work yet.

does the query return more than 1 row? If not, that's why the "error" exists ($boxRow takes the first row, and there are no more left for the next call to fetch)... — ircmaxell
– ircmaxell, Commented Dec 24, 2010 at 4:12
"MY SQL STATEMENT HERE" is different than "MY SQL STATEMENT AGAIN". duh. — zsalzbank
– zsalzbank, Commented Dec 24, 2010 at 4:12
ircmaxell - only 1 row is returned. I'm not sure I understand though. Doesn't $customerBox equal the same thing regardless of what is fetched from it? — Kyle Parisi
– Kyle Parisi, Commented Dec 24, 2010 at 4:17
rajmohan - SELECT * FROM box WHERE customer_id='$logOptions_id' — Kyle Parisi
– Kyle Parisi, Commented Dec 24, 2010 at 4:22

Community · Accepted Answer · 2023-11-17 20:38:18Z

5

The problem is because since the query returns one row, there's nothing left to fetch.

the mysql_fetch_* functions fetch the current row and then advance the row pointer to the next one. If the current row doesn't exist, it returns false. So on your second call to mysql_fetch_assoc, the pointer is on the 2nd row, but that row doesn't exist so your loop isn't executed. You have two options:

Good: Remove the while loop, and change foreach to use $boxRow instead:

foreach ($boxRow as $columnName => $value) {
    //...
}

Ok: Rewind MySQL's row pointer using mysql_data_seek:

$boxRow = mysql_fetch_array($customerBox);
mysql_data_seek($customerBox, 0);
while(...){

edited Nov 17, 2023 at 20:38

CommunityBot

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answered Dec 24, 2010 at 4:26

ircmaxell

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Comments

superUntitled · Accepted Answer · 2010-12-24 04:24:24Z

1

This may have more to do with the mysql_fetch_array() than your variable. Try to put this:

mysql_data_seek ( $customerBox , 0 );

right before the while loop starts. I am curious to see the result.

answered Dec 24, 2010 at 4:24

superUntitled

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1 Comment

ircmaxell Over a year ago

+1 since you did beat me to it (even though you had deleted your answer right after I posted my)...

pooja · Accepted Answer · 2010-12-24 04:50:09Z

0

$customerBox = mysql_query("MY SQL STATEMENT HERE");
$boxRow = mysql_fetch_array($customerBox);

while($item = mysql_fetch_field($customerBox)) { foreach ($item as $columnName => $value) { if (empty($value)) { print $columnName; } } }

answered Dec 24, 2010 at 4:50

pooja

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