Counting word occurrences in a table column

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渐次进展 2020-12-11 19:13

I have a table with a varchar(255) field. I want to get (via a query, function, or SP) the number of occurences of each word in a group of rows from this table.

If

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  •  有刺的猬
    2020-12-11 20:16

    @Elad Meidar, I like your question and I found a solution:

    SELECT SUM(total_count) as total, value
    FROM (
    
    SELECT count(*) AS total_count, REPLACE(REPLACE(REPLACE(x.value,'?',''),'.',''),'!','') as value
    FROM (
    SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(t.sentence, ' ', n.n), ' ', -1) value
      FROM table_name t CROSS JOIN 
    (
       SELECT a.N + b.N * 10 + 1 n
         FROM 
        (SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) a
       ,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) b
        ORDER BY n
    ) n
     WHERE n.n <= 1 + (LENGTH(t.sentence) - LENGTH(REPLACE(t.sentence, ' ', '')))
     ORDER BY value
    
    ) AS x
    GROUP BY x.value
    
    ) AS y
    GROUP BY value
    

    Here is the full working fiddle: http://sqlfiddle.com/#!2/17481a/1

    First we do a query to extract all words as explained here by @peterm(follow his instructions if you want to customize the total number of words processed). Then we convert that into a sub-query and then we COUNT and GROUP BY the value of each word, and then make another query on top of that to GROUP BY not grouped words cases where accompanied signs might be present. ie: hello = hello! with a REPLACE

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