PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column

Question

I am tring to perform the following sql query to check if the name that was inserted to the form already created as taxonomy name. But I keep getting this error message:

PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'test' in 'where clause': SELECT COUNT(*) FROM {taxonomy_term_data} WHERE name = test; Array ( ) in get_google_map_api() (line 79 of /Applications/MAMP/htdocs/Drupal/sites/all/modules/toodate/toodate.module).

my function is:

function get_google_map_api($item){
    $city_name = $item;
    $chack_if_is_taxonomy = (db_query("SELECT COUNT(*) FROM {taxonomy_term_data} WHERE name = ".$city_name));       
    var_dump($chack_if_is_taxonomy);
    drupal_exit();
}

Answer 1

Quick fix would be adding the missing single quotes around your variable. Forgetting the quotes can throw odd errors from this function, such as mixing a string for a column, like in your case.

There are less error prone ways to make short queries like this. See also Molot's answer.

Answer 2

Don't use db_query() unless you really have to. Build your queries with db_select(). It's harder to make SQL errors using it. Your query would look like this:

// SELECT COUNT(*) FROM {taxonomy_term_data} WHERE name = $city_name
$chack_if_is_taxonomy = db_query('taxonomy_term_data', 'ttd');
$chack_if_is_taxonomy->addField('ttd', 'COUNT(*)', 'count');
$chack_if_is_taxonomy->condition('name', $city_name, '=');

As you can see, no place to make SQL errors, and PHP bugs should be easier to spot in your favourite IDE.