Re: extracting words

am Tue, dem 22.04.2008, um 22:25:04 +0100 mailte Tarlika Elisabeth Schmitz folgendes:
> I am not quite sure whether this would be sensible or indeed at
> all possible to do in SQL:
>
> TABLE product: product_pk, product_name, department_fk
> TABLE product: department_pk, department_name
>
> example data:
>
> SELECT product_pk, department_name, product_name ... LEFT JOIN ...:
>
> 1, "cakes & desserts", "apple crumble"
> 2, "cakes & desserts", "cheese cake"
> 3, "starters & soups", "french onion soup"
>
>
> I need to extract the words from department_name and product_name
> (words are separated by spaces) and get something like:
>
> 1 cakes
> 1 desserts
> 1 apple
> 1 crumble
> 2 cakes
> 2 desserts
> 2 cheese
> 2 cake
> 3 starters
> 3 soups
> 3 french
> 3 onion
> 3 soup
>

A little function (author: David Fetter)

-- split a string to rows, by David Fetter
CREATE OR REPLACE FUNCTION split_to_rows(TEXT, TEXT) RETURNS SETOF TEXT
STRICT
LANGUAGE sql
AS $$
SELECT (string_to_array($1, $2))[s.i]
FROM generate_series(
1,
array_upper(string_to_array($1, $2), 1)
) AS s(i);
$$;

And now:

test=*# select * from product ;
id | val1 | val2
----+------------------+-------------------
1 | cakes & desserts | apple crumble
2 | cakes & desserts | cheese cake
3 | starters & soups | french onion soup
(3 rows)

test=*# select id, split_to_rows(replace(val1 || ' ' || val2,' &',''),' ') as col1 from product;
id | col1
----+----------
1 | cakes
1 | desserts
1 | apple
1 | crumble
2 | cakes
2 | desserts
2 | cheese
2 | cake
3 | starters
3 | soups
3 | french
3 | onion
3 | soup
(13 rows)

HTH, Andreas
--
Andreas Kretschmer
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