How to extract the nth word and count word occurrences in a MySQL string?

Question

I would like to have a mysql query like this:

select <second word in text> word, count(*) from table group by word;

All the regex examples in mysql are used to query if the text matches the expression, but not to extract text out of an expression. Is there such a syntax?

Answer 1

The following is a proposed solution for the OP's specific problem (extracting the 2nd word of a string), but it should be noted that, as mc0e's answer states, actually extracting regex matches is not supported out-of-the-box in MySQL. If you really need this, then your choices are basically to 1) do it in post-processing on the client, or 2) install a MySQL extension to support it.

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BenWells has it very almost correct. Working from his code, here's a slightly adjusted version:

SUBSTRING(
  sentence,
  LOCATE(' ', sentence) + CHAR_LENGTH(' '),
  LOCATE(' ', sentence,
  ( LOCATE(' ', sentence) + 1 ) - ( LOCATE(' ', sentence) + CHAR_LENGTH(' ') )
)

As a working example, I used:

SELECT SUBSTRING(
  sentence,
  LOCATE(' ', sentence) + CHAR_LENGTH(' '),
  LOCATE(' ', sentence,
  ( LOCATE(' ', sentence) + 1 ) - ( LOCATE(' ', sentence) + CHAR_LENGTH(' ') )
) as string
FROM (SELECT 'THIS IS A TEST' AS sentence) temp

This successfully extracts the word IS