What?
This is an article to document how to output the most frequently used words in a MySQL database column.

How?
Note this only applies to MySQL. So the following query will return a count of each word in your database column by order of most used first (replace 'mydbprefix_content' with the name of your database table AND `introtext` with the name of your column): 
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(ExtractValue(t.`introtext`, '//text()'), ' ', n.n), ' ', -1) `value`
        FROM `mydbprefix_content` 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(ExtractValue(t.`introtext`, '//text()')) - LENGTH(REPLACE(ExtractValue(t.`introtext`, '//text()'), ' ', '')))
        ORDER BY `value`
    ) AS x
    GROUP BY x.`value`
) AS y
WHERE LENGTH(`value`)>5
AND TRIM(`value`) NOT IN ('Article','This',' ','content','component','applies','because','doesn''t')
GROUP BY `value`
ORDER BY `total` DESC
LIMIT 0,50;
Additional Note(s):
  • I have added a WHERE clause which omits words less than 5 characters in length, and some other words not to count.
  • I have added the ORDER BY to give me the highest count first in descending order.
  • I have added a LIMIT to only return the top 50 words.

Source(s):