MySQL Max

[Speedysnail6]

Hello,

This is my PHP/MySQL code.

$result = mysqli_query($con,"SELECT MAX(ID) FROM lessons");

while($row = mysqli_fetch_array($result))
  {
  echo $row['ID'];
  }

And yet, nothing is entered on the page. What am I doing wrong?

[Barand]

You need a column alias for the MAX expression. Try

 

SELECT MAX(ID) as ID ....

[Speedysnail6]

Thank you! That worked! I appreciate it

[vinny42]

FYI: you don't absolutely need the alias, it just makes life easier. The data you select becomes available as the expression that you selected, so

 

echo $row['MAX(ID)'];

 

would also work, but it's not pretty, it promotes bugs, it's bad.

[mac_gyver]

or use echo $row[0]; since fetch_array() is being used.

[vinny42]

 

or use echo $row[0]; since fetch_array() is being used.

 

fetch_array() will also fill numeric indexes, true, and that would be just as dangerous as using the original expression as an index.

 

A clear, descriptive alias is the best option, you can modifiy the query as much as you want; as long as the data comes out under the correct alias the rest of the code doesn't care.