Already fixed. It was because of nested field in meta key, for example, if you have cite field inside left_column group field, you shoud set key as left_column_city.
And the second issue i used meta_key instead of key.
So the right arguments should be like this:
$args = array (
'role' => 'subscriber',
'order' => 'ASC',
'orderby' => 'display_name',
'number' => $num,
'offset' => $offset,
'meta_query' => array(
'relation' => 'AND',
)
);
if($city != ''){
$args['meta_query'][] = array(
array(
'key' => 'left_column_city',
'value' => $city,
'compare' => 'LIKE',
),
);
}
if($loc != ''){
$args['meta_query'][] = array(
array(
'key' => 'left_column_state',
'value' => $loc,
'compare' => '=',
),
);
}
if($cat != ''){
$args['meta_query'][] = array(
array(
'key' => 'left_column_specialties',
'value' => $cat,
'compare' => 'LIKE'
)
);
}