MySQL: Count occurrences of words in a column
- Joel Lipman
- MySQL
- Hits: 6214
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.
Sometimes it is critical to ensure a group of queries are all executed successfully to maintain the integrity of our data. Let's say we have a banking app where we need to subtract funds from one account and add funds to another:
$mysqli->query ("UPDATE 'accounts' SET 'balance' = 'balance'-1000000 WHERE 'user' = 'Bob'"); $mysqli->query ("UPDATE 'accounts' SET 'balance' = 'balance'+1000000 WHERE 'user' = 'Fred'");
What if one of the queries fails? To mitigate the chances of misplacing our millions due to some possible error we must ensure that both queries are executed with the expected result before committing any changes to the data. This where transactions are useful. We can run the queries, then check if some conditions are met before committing the changes in the data:
UPDATE `mytable` SET `myColumn` = TRIM(CHAR(9) FROM TRIM(`myColumn`));Source: Stack Overflow - How to Remove Tabs
UPDATE `table_to_update` a INNER JOIN `table_to_read` b ON a.`CountryName` COLLATE utf8_general_ci LIKE b.`CountryName` COLLATE utf8_general_ci SET a.`ccTLD` = b.`ccTLD`
ThisDate ThisDay StartTime TimeOut TimeIn EndTime TotalTimeToday TotalTimeWeek ----------- ----------- ---------- -------- ------- -------- -------------- ------------- 2013-12-02 Monday 09:00 12:00 13:00 17:00 7:00 7:00 2013-12-03 Tuesday 08:45 12:00 13:30 17:45 7:30 14:30 2013-12-04 Wednesday 09:00 12:30 13:30 17:00 7:00 21:30 2013-12-05 Thursday 10:00 12:15 12:45 17:15 7:45 29:15 2013-12-06 Friday 07:00 12:00 13:00 16:30 8:30 37:45 2013-12-07 Saturday - - - - 0:00 37:45 2013-12-08 Sunday 03:00 04:00 - - 4:00 41:45
-- return all records that contain non-alphanumeric characters SELECT * FROM myTable WHERE myColumn NOT REGEXP '^[A-Za-z0-9]+$'; -- return all records that are non-alphanumeric but ignore underscores SELECT * FROM myTable WHERE myColumn NOT REGEXP '^[A-Za-z0-9\\_]+$';
-- where @ThisSearch is a posted (and sanitized) variable SET @ThisSearch:="Brains"; SELECT columnID, columnFullName, CASE WHEN columnFirstName LIKE @ThisSearch THEN 20 WHEN columnFullName LIKE @ThisSearch THEN 10 WHEN columnLastName LIKE @ThisSearch THEN 10 WHEN columnFullName LIKE @ThisSearch THEN 1 END as relevance FROM myTable WHERE s.columnPublished
Ok is it just me who does everything slowly and badly until someone comes along and says why are you doing it like...
What? This article is to remind me how to create a blank weekly timesheet which reads the duration of events from a...
What? Week Ending Date has been requested a lot more frequently now. It's an odd one but the example below shows how...
What? So this is a quick article on how to install the mySQL add-on for Oracle SQL Developer v3.0.04. Why? I've used...
What? So this is an article to serve as documentation for one of the data sources available to download for FREE from...
The scenario is that I wanted a PHP/MySQL extension created which needs to launch a query to find all columns across...
What? This is an article to document how to output the most frequently used words in a MySQL database column. How? Note this...
user server used page create where file following table database find parameter case first using note deluge order would code report added license google windows files work need client script name time source creator form data version system uploaded display error website field zoho joomla list date function mysql value JoelLipman.Com