Mysql Query returning 0 results

Given the values in these 2 rows, why does my query return 0 rows and how can the query be rewritten to work properly?

meta_id post_id meta_key   meta_value
   1422      73 wpcf-milk      22
   1423      73 wpcf-mw        -7

SQL Query:

   SELECT * FROM wp_postmeta
    WHERE post_id = 73 
    AND ( meta_key = 'wpcf-mw' AND meta_value BETWEEN -8 AND 200 )
    AND ( meta_key = 'wpcf-milk' AND meta_value BETWEEN 20 AND 200 )

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2 comments

  1. SELECT * FROM wp_postmeta 
    WHERE post_id = 73 
      AND (( meta_key = 'wpcf-mw' AND meta_value BETWEEN -8 AND 200 ) 
      **OR** ( meta_key = 'wpcf-milk' AND meta_value BETWEEN 20 AND 200 ))
    

    Change AND by OR.

  2. There are essentially two ways of doing this. One is roughly as follows:

    SELECT post_id
         , MAX(CASE WHEN meta_key = 'wpcf-milk' THEN meta_value END) wpcf_milk
         , MAX(CASE WHEN meta_key = 'wpcf-mw' THEN meta_value END) wpcf_mw 
      FROM wp_postmeta 
     GROUP 
        BY post_id 
    HAVING wpcf_milk BETWEEN 20 AND 200 
       AND wpcf_mw BETWEEN -8 AND 200;
    

    The other approach involves OUTER JOINs and is slightly faster, but slightly more tedious to type out – so I’ll leave it to others.