WP_Query post_tilte search in posts table

Question

Here is my array which I am trying to get "apple" keyword in post table but it can't work like I want. Please let me know what is wrong with my array?

Array
(
    [paged] => 1
    [posts_per_page] => 50
    [tax_query] => Array
        (
            [0] => Array
                (
                    [taxonomy] => product_type
                    [field] => slug
                    [terms] => Array
                        (
                            [0] => chipin
                        )

                    [operator] => NOT IN
                )

        )

    [status] => publish
    [orderby] => date
    [order] => DESC
    [meta_query] => Array
        (
            [0] => Array
                (
                    [key] => _stock_status
                    [value] => instock
                )

            [1] => Array
                (
                    [key] => post_title
                    [value] => apple
                    [compare] => LIKE
                )

            [2] => Array
                (
                    [relation] => OR
                )

        )

    [title_filter] => apple
    [title_filter_relation] => OR
    [post_type] => product
)

Here is query

SELECT SQL_CALC_FOUND_ROWS  bhs_posts.ID
                    FROM bhs_posts  INNER JOIN bhs_postmeta ON ( bhs_posts.ID = bhs_postmeta.post_id )  INNER JOIN bhs_postmeta AS mt1 ON ( bhs_posts.ID = mt1.post_id )
                    WHERE 1=1  AND ( 
  bhs_posts.ID NOT IN (
                SELECT object_id
                FROM bhs_term_relationships
                WHERE term_taxonomy_id IN (918)
            )
) AND ( 
  ( bhs_postmeta.meta_key = '_stock_status' AND bhs_postmeta.meta_value = 'instock' ) 
  AND 
  ( mt1.meta_key = 'post_title' AND mt1.meta_value LIKE '{c914ad731b1921eeb5b858d7b618d23619ec92314bf850d67e343f6599dee9cc}apple{c914ad731b1921eeb5b858d7b618d23619ec92314bf850d67e343f6599dee9cc}' )
) AND ((bhs_posts.post_type = 'product' AND (bhs_posts.post_status = 'publish')))
                    GROUP BY bhs_posts.ID
                    ORDER BY bhs_posts.post_date DESC
                    LIMIT 0, 50

Database table:

If I can make query like following then get proper result but I don't know how to change array in Wp

SELECT SQL_CALC_FOUND_ROWS  bhs_posts.ID
                    FROM bhs_posts  INNER JOIN bhs_postmeta ON ( bhs_posts.ID = bhs_postmeta.post_id )  INNER JOIN bhs_postmeta AS mt1 ON ( bhs_posts.ID = mt1.post_id )
                    WHERE 1=1  AND ( 
  bhs_posts.ID NOT IN (
                SELECT object_id
                FROM bhs_term_relationships
                WHERE term_taxonomy_id IN (918)
            )
) AND ( 
  ( bhs_postmeta.meta_key = '_stock_status' AND bhs_postmeta.meta_value = 'instock' ) 
  AND 
  ( bhs_posts.post_title LIKE 'apple%' )
) AND ((bhs_posts.post_type = 'product' AND (bhs_posts.post_status = 'publish')))
                    GROUP BY bhs_posts.ID
                    ORDER BY bhs_posts.post_date DESC
                    LIMIT 0, 50

Answer 1

You added title inside $args['meta_query'] and that's why your query doesn't work. Checking the documentation (get_posts / WP_Query) you will find the available parameters, among them title and s.

$args = array(
    's'         => 'apple',
    'post_type' => 'product'
    //
    // other parameters
    // 'status`, 'orderby', 'meta_query', ...
)
$posts = get_posts($args);

If you use the title parameter - the exact match of the post title will be checked.
bhs_posts.post_title = 'some text'

If you use s parameter - (in simplification) the phrase will be splited and searched in the post title, content and excerpt .

((bhs_posts.post_title like '%some%' OR bhs_posts.post_excerpt like '%some%' OR bhs_posts.post_content like '%some%')
AND (bhs_posts.post_title like '%text%' OR bhs_posts.post_excerpt like '%text%' OR bhs_posts.post_content like '%text%'))

If you want to search only in the title of a post, you will need to use posts_search or posts_where filter to modify the query.

add_filter('posts_search', 'se414324_title_search', 100, 2)
function se414324_title_search( $search, $wp_query )
{
    global $wpdb;

    $qv = &$wp_query->query_vars;
    if ( !isset($qv['wpse_title_search']) || 0 == strlen($qv['wpse_title_search']) )
        return $search;

    $like = $wpdb->esc_like( $qv['wpse_title_search'] ) . '%';
    $search = $wpdb->prepare( " AND  {$wpdb->posts}.post_title LIKE %s", $like );
    return $search;
}

To modify only selected queries, and not all performed by WP, we use our own parameter name, here wpse_title_search in $args array.

$args = array(
    'wpse_title_search' => 'apple',
    'post_type' => 'product',
    //
    // other parameters
    // 'status`, 'orderby', 'meta_query', ...
)
$myquery = new WP_Query($args);

OR

// "suppress_filters" is necessary for the filters to be applied
$args = array(
    'wpse_title_search' => 'apple',
    'post_type' => 'product',
    'suppress_filters' => false,
    //
    // other parameters
    // 'status`, 'orderby', 'meta_query', ...
)
$posts = get_posts($args);

Answer 2

/* Use simple Query with s parameter */

$args = array(      
    'post_type'   => 'product',
    's'           => 'apple',
    'post_status' => 'publish',
    'posts_per_page' => -1,    
);

$wp_query = new WP_Query($args);