How to update a custom field in all posts with the value of another custom field in the same post?

$enddatevar = get_post_meta( $post_id, $key = 'enddate', $single = false);

$post_id is not defined, either declare it beforehand, or use $post->ID.

update_post_meta( $post->ID, 'promote', '$enddatevar' );

‘$enddatevar’ shouldnt be inside quotes.

Related Posts:

  1. Query to sort a list by meta key first (if it exists), and show remaining posts without meta key ordered by title
  2. Max length of meta_value
  3. SELECT max(meta_value) FROM wp_postmeta WHERE meta_key=’price’… stops working when value is over 999
  4. How can I display all values of a custom field from posts with a certain value of another custom field or from certain post types?
  5. get_pages sort alphabetically by meta value
  6. Assign/update the custom field value for all posts
  7. Order by custom field date with ASC order
  8. How to break meta values into different items and avoid duplicates?
  9. WP_query : meta_key with custom rule for specific value
  10. How to sort category by custom field value
  11. trim custom field text value and show (…)
  12. Query post order by post and desc not working
  13. How to wrap meta values seperated by comma in ? [closed]
  14. How to create a Custom Meta Box with Name/Value Admin User Input Fields?
  15. Run a check for multiple meta key values
  16. Filter by custom field (meta_key) using JSON API
  17. Removing link ” from ” on meta_value in custom feilds
  18. Sort alphabetically by custom field
  19. pre_get_posts : only get posts by wp_usermeta value
  20. meta_value and meta_key filtering returning no posts [closed]
  21. IF Custom field value equals ZERO
  22. List custom field values ​​in alphabetical order without repetition
  23. Update post meta custom field using block editor
  24. How to add custom filed value after in wp post title
  25. Sortable Custom Columns not sorting correct
  26. query_posts with meta_value
  27. Show array of meta_value in Edit Post Coloum
  28. Making WP_Query limit results by date before today where date is a meta_query
  29. User query – getting values for custom meta keys/fields
  30. get posts based on non-single metadata
  31. Set class if a meta value is set within post archive
  32. Query to sort a list by meta key first (if it exists), and show remaining posts without meta key ordered by title
  33. Create Shortcode shows only posts with custom_field meta
  34. 4 Unique Random Posts based on Custom Field Values
  35. Custom Field: Display only if a specific key is selected outside the loop
  36. WP Query Args – search by meta_key or title
  37. Saving multiple custom meta box fields
  38. get Custom field label (select/dropdown) on front end
  39. Individual Widgets per Page
  40. Add custom fields to search
  41. How to add add_meta_box to specific Page Template?
  42. How to get users by a custom field / by user meta data?
  43. Auto sort the wp-admin post list by a meta key
  44. Add custom field to image editor
  45. Show User Their Password
  46. TinyMCE in Custom Metabox not loaded after upgrading from WP 3.1.4 to WP 3.2
  47. ajax delete value from custom field array
  48. How can I sort get_users() by any value (last_name, user defined fields and more)
  49. Custom field for default gallery
  50. After moving my site from a dev subdomain, to root, all my custom meta data is gone
  51. Gravity Forms: Create fields programmatically
  52. WordPress Custom Field Should be Unique. Is it possible?
  53. all tincymce’s switch when updating page after changing from html to text in custom metabox
  54. Author Page Custom Query WHERE author OR [post meta value] OR [post meta value]
  55. Add source URL from Feed WordPress (Syndication) plugin to a custom field in post editor
  56. List custom taxonomy terms from custom field
  57. How do I create a column in Users list and display user data from custom registration field
  58. Better Method for Multiple Meta Boxes
  59. Product Custom Fields with HTML and JS
  60. Add new image block, set default class name and update it using Javascript
  61. Add image to menu item with ACF
  62. Client PDF Upload (Catalogue) – Automatically update link to PDF
  63. How to load an assets based on custom field value?
  64. Adding auto-complete to custom gravity field not working
  65. Search in Archive Pages by subcategory, tag, custom field and year
  66. Get image url using image id
  67. Using a custom field inside a shortocde
  68. Add Custom Profile Field as Notes
  69. ul list with only as many li’s as filled custom fields
  70. Is there a way to dump all registered sidebar/widget?
  71. How to hide post meta
  72. ACF Plugin How to make the customer add more fields in the post?
  73. custom field in admin columns
  74. get_post_meta returns 0
  75. Users uploaded image and matching an id or taxonomy
  76. Adding data to User profile
  77. How can I change author of posts to the value of one of the custom field of the posts?
  78. Let any visitors delete a post if they know Id nr & password?
  79. update a custom field with the value of another existing custom field
  80. Post meta data not showing in frontend, until hitting ‘update’ button
  81. Ordering posts by custom fields (Date)
  82. PHP and Shortcode Combination
  83. Retrieving Advanced Custom Field within Shortcode Function [closed]
  84. How to properly get popular Posts by multiple Values
  85. Sorting Posts with meta value not working
  86. Query Custom Fields in Searchform
  87. Get custom fields when hover link of post
  88. WP Query multiple select form – meta_query help
  89. update_post_meta not working in action hook
  90. Group pages by custom field values
  91. Convert many posts from having a specific meta_key to use a post_format
  92. How to check if custom field exists in this widget query
  93. display loop only if a post meta data exist
  94. Add Custom field under the post title [closed]
  95. Check if a field is capitalized?
  96. Can’t sort custom column on user.php by number / meta_value_num?
  97. Need to call this php function inside a modal window from text widget
  98. Add CSS class to posts with certain meta key
  99. Best way for managing images of ads banners
  100. Crop custom image size vs actual size
error code: 523