How Can I Extract the Nth Word and Count its Occurrences in MySQL and PostgreSQL?

Extracting the Nth Word and Count Word Occurrences in MySQL

The question posed concerns the possibility of a MySQL query that can extract a specific word from a text string and count its occurrences. The example provided seeks to extract the second word from the text.

Query Solution for Postgres

While MySQL does not natively support direct regex match extraction, other databases like PostgreSQL provide a more straightforward approach. In PostgreSQL, the following query could be used:

SELECT word, count(*)
FROM (
  SELECT SPLIT_PART(text, ' ', 2) AS word
  FROM (SELECT 'THIS IS A TEST' AS text) AS tmp
) AS words
GROUP BY word;

This query uses the SPLIT_PART function to split the text into individual words based on spaces and extracts the second word. The resulting table groups words by their occurrence.

Workaround for MySQL

For MySQL, a different approach is required as direct regex extraction is not supported. One workaround involves using a combination of substring and locate functions:

SELECT SUBSTRING(
  text,
  LOCATE(' ', text) + CHAR_LENGTH(' '),
  LOCATE(' ', text, ( LOCATE(' ', text) + 1 ) - ( LOCATE(' ', text) + CHAR_LENGTH(' ') )
) AS word, count(*)
FROM (SELECT 'THIS IS A TEST' AS text) AS tmp
GROUP BY word;

This query locates the position of the first space in the text, which would be after the first word. It then adds the length of a space to this position to start the extraction of the second word. The length of the extracted substring is calculated by locating the next space and subtracting the starting position from it.

This method requires adjustment for extracting different nth words.

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