Question

Im trying to get this query to work but i get this error:
Unknown column ‘zips.city’ in ‘having clause’

`$query = "SELECT
    zips.*
    FROM
    zips
    HAVING
    zips.city LIKE '%$city%' 
    AND
    zips.stateabbr LIKE '%$state%' 
    LIMIT 1";
$result = mysql_query($query) or die (mysql_error());`

my zips table has a city column, so im not sure what the problem is, i know im accessing the database because i can run this query with no errors:

$zip1query = "SELECT 
         zips.*
         FROM 
         zips
         WHERE
         zips.zip = '$zip'              
         ";

any advice would be much appreciated! thanks!

Answer 1

The having clause doesn’t mean the same thing as the where clause : when running a simple query, you should use where — which is what you did in your second query, that works.

having is used when the condition has to be applied on the result of a group by clause.

Which means that, here, your query should be build this way :

$query = "SELECT zips.*
    FROM zips
    where zips.city LIKE '%$city%' 
        AND zips.stateabbr LIKE '%$state%' 
    LIMIT 1";

With that, if you still have an error about a non-existing or not-found column (at least for city and/or stateabbr), it’ll be because that column doesn’t exist in your table.

In this case, there is not much we can do : you’ll have to check the structure of your table, to determine which columns it contains.

You can check that structure using a web-based tool like phpMyAdmin, or using an SQL instruction such as :

desc zips;

For reference, quoting MySQL’s manual page for select :

The SQL standard requires that HAVING
must reference only columns in the
GROUP BY clause or columns used in
aggregate functions.
…

Do not use HAVING for items that
should be in the WHERE clause.

For example, do not write the
following:

SELECT col_name FROM tbl_name HAVING col_name > 0;

Write this instead:

SELECT col_name FROM tbl_name WHERE col_name > 0;

…

The HAVING clause can refer to
aggregate functions, which the WHERE
clause cannot