Question

Below is my database table structure in MySQL – I want to match specific dynamic field values with each other as described below:

meta_id post_id     meta_key            meta_value
616     472         "machine_type"      "Combined pipe cutting"
561     472         _edit_lock          1354882015:1
560     472         _edit_last          1
562     472         _mf_write_panel_id  1
565     472         _wp_page_template   machine_layout.php
617     472         jet_filter          
618     472         "length_x_axis"     "3000mm"
619     472         machine_image       488

Above I have "" quote marked the fields – against which I have to apply the query and fetch result.

Now here, I want to check meta_key field and meta_value field and want to retrieve the matching post_id field’s value.

For ex: my first parameter on meta_key will be length_x_axis and its matching value in meta_value will be 3000mm and AND condition with it will be meta_key for machine_type and its matching value in meta_value will be Combined pipe cutting.

And the result I need is post_id value 472

This is a complete dynamic wordpress wp_postmeta table which will have many records with conditions like this.

Earliest MySQL Query in result will be appreciated.

Please forgive me if any spell mistakes, I have tried my best to explain the community my question.

Please help !

Answer 1

I’m not sure what you really want, but i think that is the query you are looking for:

SELECT t1.post_id 
FROM mytable t1 inner join mytable t2 on t1.post_id = t2.post_id 
WHERE t1.meta_key = "length_x_axis" and t1.meta_value="3000mm" 
AND t2.meta_key="machine_type" and t2.meta_value="Combined pipe cutting"