How to return the Size of VARCHAR field?

Anon

Is there a function that can be done in SELECT to return the SIZE of a VARCHAR field? For example, I have a table that contains a row that has "User" as a VARCHAR(15). Can I use a SELECT User from <usertable>, but return only the SIZE of the VARCHAR? Thanks

Anon

You didn't mention what RDBMS you are using.

In MySQL you can do this:

describe usertable user;

Which will return details about the column. The field you want is named "Type" and in this case would literally be "varchar(15)" which you can parse to get the size.

Anon

Thanks for the reply, but is there another way through a function? Like SELECT count(Username) FROM user; will give the number of usernames in the table. Is there something like SELECT sizof(Username) FROM user; to get the VARCHAR size? Thanks.

Anon

you can always use PHP's strlen() function once the data is pulled out of the db.

Anon

But strlen() gives only the length of the data stored, not the actual sizeof the field. Reason for this is to allow someone to modify the tables for a username or password to allow larger or smaller VARCHAR field. I can test the field through the HTML by getting the current VARCHAR and informing the user that the VARCHAR is the maximum number of chars, then check if they exceeded that and report an error instead of the data just being accepted and truncated.

flipis

If you use this:

$query=mysql_query("SHOW FIELDS FROM tablename",$Connection);
$Rows = mysql_num_rows($query);
for($i=0;$i<$Rows;$i++){
$FieldName[$i] = mysql_result($query,$i,"Field");
$FieldType[$i] = mysql_result($query,$i,"Type");
$FieldNull[$i] = mysql_result($query,$i,"Null");
$FieldKey[$i] = mysql_result($query,$i,"Key");
$FieldDefault[$i] = mysql_result($query,$i,"Default");
$FieldExtra[$i] = mysql_result($query,$i,"Default");
}

You can trim the FieldType value. It will return somethign like VARCHAR(15).

Like that, if you are using MySQL.

fLIPIS

Anon

No.