WordPress MySQL SQL Query Error in WPDB Class

WordPress plug-ins users or external scripts developers may encounter problems on when trying to perform query or manipulation on MySQL database by using $wpdb class, a class of functions for all database manipulations based on the ezSQL. $wpdb WordPress class provides easy way to access to database tables without the need to manually code the database connection syntax in PHP again. $wpdb provides several functions to access, retrieve, select, delete, update or manipulate the data in the database such as query, get_var, get_row, get_col, get_results, escape, show_errors, hide_errors, get_col_info, and flush.

When using these $wpdb to parse SQL statements as in plug-ins or external scripts or even WordPress code itself the following error or similar error may appear.

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘ORDER BY post_date ASC LIMIT 1’ at line 1]
SELECT ID, post_title FROM wp_posts WHERE post_date > ” AND post_date < ‘2006-08-28 09:03:57’ AND post_status = ‘publish’ AND ID != ORDER BY post_date ASC LIMIT 1

or (the following from bsuite B2V6),

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ’s pages’ ELSE LEFT(b.post_title, 60) END AS title, SUM(a.hits_reads) AS sor’ at line 4]
SELECT a.post_id AS post_id, CASE WHEN b.post_title IS NULL THEN ‘Alice’s Home’ ELSE LEFT(b.post_title, 60) END AS title, SUM(a.hits_reads) AS sort_order, CONCAT(’Tot: ‘, FORMAT(SUM(a.hits_reads), 0), ‘, Avg: ‘, FORMAT((SUM(a.hits_reads)) / ((TO_DAYS(NOW()) – TO_DAYS(MIN(a.bstat_date))) + 1), 0), ‘, Max: ‘, FORMAT(MAX(a.hits_reads), 0), ‘’) AS note FROM wp_bstat_hits a LEFT JOIN wp_posts b ON (a.post_id = b.ID) WHERE bstat_date > ‘2006-08-03′ GROUP BY a.post_id ORDER BY sort_order DESC LIMIT 5

One of the reason for the errors is caused by post_ID or ID variable that represent the ID of the WordPress post. Depending on which version of PHP, MySQL or WordPress you used, the $post_id or $id or $post->ID can be placed within single quote (‘) as the workaround or resolution to avoid or solve the error.