Nested array issue in meta_query

Question

I am using following meta_query to search blog post according to following search criteria,

search logic :

1. if expire date set, check the expiry of the post, otherwise just include it
2. if country($_country) in the filters, search for that particular country with above expire date rule. otherwise just apply the expire date rule.

meta_query:

$expire_meta_1 = array(
    'key' => '_simple_fields_fieldGroupID_3_fieldID_7_numInSet_0',
    'value' => '',
    'compare' => 'NOT EXISTS'
);

$expire_meta_2 = array(
    'key' => '_simple_fields_fieldGroupID_3_fieldID_7_numInSet_0',
    'value' => date("Y-m-d"),
    'compare' => '>=',
    'type' => 'DATE'
);

if($_country!=''){
    $country_meta = array(
        'key' => '_simple_fields_fieldGroupID_3_fieldID_8_numInSet_0',
        'value' => $_country,
        'compare' => '='
    );
    $args['meta_query'] = array( 'relation' => 'AND', array( 'relation' => 'OR', $expire_meta_1, $expire_meta_2), $country_meta);
} else{
    $args['meta_query'] = array( 'relation' => 'OR', $expire_meta_1, $expire_meta_2);
}

the issue is, if it is country search, post should set the expire date. but I need to select the posts also not set the expire date.(if set check the expiry, that is anyway working).

But if I am not searching for specific country, the expire date rule(rule 1) is working properly.

Anybody have any idea what is my mistake. Any help would be appreciate. I hope question is clear, otherwise I can provide more details, please let me know. Thanks in advance.

Answer 1

Finally I found the real issue after few hours of debugging.

I'm using simple fields to save the expire date and country values. So in simple field even we are not setting anything it is still save empty string in the database. So when I check the non existing fields, it is not giving correct results, however when I search of empty string(like below) it is giving me the correct output.

$expire_meta_1 = array(
    'key' => '_simple_fields_fieldGroupID_3_fieldID_7_numInSet_0',
    'value' => '',
    'compare' => '='
);

I should thanks to @Sumit to help me to figure out the real issue.