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Data cleaning: Difference between revisions
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→Counting number of duplicate occurrence
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* Google spreadsheet add-on: [https://www.ablebits.com/google-sheets-add-ons/remove-duplicates/howto.php Remove Duplicates for Google Sheets help] | * Google spreadsheet add-on: [https://www.ablebits.com/google-sheets-add-ons/remove-duplicates/howto.php Remove Duplicates for Google Sheets help] | ||
=== Counting number of | === Counting number of occurrences (or frequency) === | ||
MySQL: find the number of duplicate occurrence between list_a & list_b which using the same primary key: column name {{kbd | key = id}} | MySQL: find the number of duplicate occurrence between list_a & list_b which using the same primary key: column name {{kbd | key = id}} | ||
* {{kbd | key = SELECT count(DISTINCT(`id`)) FROM `list_a` WHERE `id` IN (SELECT DISTINCT(`id`) FROM `list_b`) ; }} | * {{kbd | key = SELECT count(DISTINCT(`id`)) FROM `list_a` WHERE `id` IN (SELECT DISTINCT(`id`) FROM `list_b`) ; }} | ||