Title: SQL problem
Last modified: June 9, 2025

---

# SQL problem

 *  Resolved [jkacher](https://wordpress.org/support/users/jkacher/)
 * (@jkacher)
 * [11 months ago](https://wordpress.org/support/topic/sql-problem-8/)
 * Clicking Global Filter gets this error:
   _Illegal mix of collations (utf8mb4\_unicode\
   _ci,COERCIBLE) and (utf8mb4\_unicode\_520\_ci,COERCIBLE) for operation ‘like’_
 * Perhaps I have some foreign characters in the data, how can I check?

Viewing 4 replies - 1 through 4 (of 4 total)

 *  Thread Starter [jkacher](https://wordpress.org/support/users/jkacher/)
 * (@jkacher)
 * [11 months ago](https://wordpress.org/support/topic/sql-problem-8/#post-18504379)
 * This happened after I replaced the source from table to view consisting of two
   tables, and used with one function. The only _utf8mb4\_unicode\_520\_ci_ tables
   are those used by wordpress. My tables use _utf8mb4\_unicode\_ci_
 *  Plugin Contributor [Kim L](https://wordpress.org/support/users/kimmyx/)
 * (@kimmyx)
 * [11 months ago](https://wordpress.org/support/topic/sql-problem-8/#post-18504826)
 * Hi [@jkacher](https://wordpress.org/support/users/jkacher/),
 * Thanks for the post.
 * Could you [send us a ticket](https://wpdataaccess.com/contact/) regarding this
   issue? We might need to take a closer look at your data source.
 * We’ll wait for your response!
 *  Thread Starter [jkacher](https://wordpress.org/support/users/jkacher/)
 * (@jkacher)
 * [10 months, 4 weeks ago](https://wordpress.org/support/topic/sql-problem-8/#post-18505802)
 * I did respond in the email. I traced the problem all the way to the Group_concat()
   function in MariaDB, it adds a Separator that is of a different collation. Your
   Global Filter uses a simple like ‘%x%’ , and it went all the way down through
   View to my function. I had to materialize the View first, so your Global Filter
   worked on the result. To do this I set the Algorithm=Temptable in the create 
   view, that solved the problem. So no need for a ticket, thanks for all the support
   you give us.
 *  Plugin Contributor [Kim L](https://wordpress.org/support/users/kimmyx/)
 * (@kimmyx)
 * [10 months, 4 weeks ago](https://wordpress.org/support/topic/sql-problem-8/#post-18507276)
 * Hi [@jkacher](https://wordpress.org/support/users/jkacher/),
 * Thanks a lot for the update.
 * We’re glad you were able to narrow down the cause. 🙏
 * Feel free to create a new topic if you have new questions.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘SQL problem’ is closed to new replies.

 * ![](https://ps.w.org/wp-data-access/assets/icon-256x256.png?rev=3299063)
 * [WP Data Access – App Builder for Tables, Forms, Charts, Maps & Dashboards](https://wordpress.org/plugins/wp-data-access/)
 * [Support Threads](https://wordpress.org/support/plugin/wp-data-access/)
 * [Active Topics](https://wordpress.org/support/plugin/wp-data-access/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/wp-data-access/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/wp-data-access/reviews/)

 * 4 replies
 * 2 participants
 * Last reply from: [Kim L](https://wordpress.org/support/users/kimmyx/)
 * Last activity: [10 months, 4 weeks ago](https://wordpress.org/support/topic/sql-problem-8/#post-18507276)
 * Status: resolved