Execute a JOIN N times - possible in Postgres?
Let's say I have a series of similar subqueries, and I want to join those subqueries N times.
For example, something like this:
SELECT
*
FROM
records
FOR i IN 1..N LOOP
JOIN (SELECT * FROM records where records.id = i) as i::text
END LOOP
... which I know isn't valid. Is there a way to accomplish this?
postgresql loops join
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
add a comment |
Let's say I have a series of similar subqueries, and I want to join those subqueries N times.
For example, something like this:
SELECT
*
FROM
records
FOR i IN 1..N LOOP
JOIN (SELECT * FROM records where records.id = i) as i::text
END LOOP
... which I know isn't valid. Is there a way to accomplish this?
postgresql loops join
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
Please Edit your question and add some sample data and the expected output based on that data. Formatted text please, no screen shots. edit your question - do not post code or additional information in comments.
– a_horse_with_no_name
Nov 20 '18 at 21:48
add a comment |
Let's say I have a series of similar subqueries, and I want to join those subqueries N times.
For example, something like this:
SELECT
*
FROM
records
FOR i IN 1..N LOOP
JOIN (SELECT * FROM records where records.id = i) as i::text
END LOOP
... which I know isn't valid. Is there a way to accomplish this?
postgresql loops join
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
Let's say I have a series of similar subqueries, and I want to join those subqueries N times.
For example, something like this:
SELECT
*
FROM
records
FOR i IN 1..N LOOP
JOIN (SELECT * FROM records where records.id = i) as i::text
END LOOP
... which I know isn't valid. Is there a way to accomplish this?
postgresql loops join
postgresql loops join
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
asked Nov 20 '18 at 19:43
Greg Matthew Crossley
340314
340314
Please Edit your question and add some sample data and the expected output based on that data. Formatted text please, no screen shots. edit your question - do not post code or additional information in comments.
– a_horse_with_no_name
Nov 20 '18 at 21:48
add a comment |
Please Edit your question and add some sample data and the expected output based on that data. Formatted text please, no screen shots. edit your question - do not post code or additional information in comments.
– a_horse_with_no_name
Nov 20 '18 at 21:48
Please Edit your question and add some sample data and the expected output based on that data. Formatted text please, no screen shots. edit your question - do not post code or additional information in comments.
– a_horse_with_no_name
Nov 20 '18 at 21:48
Please Edit your question and add some sample data and the expected output based on that data. Formatted text please, no screen shots. edit your question - do not post code or additional information in comments.
– a_horse_with_no_name
Nov 20 '18 at 21:48
add a comment |
2 Answers
2
active
oldest
votes
Yes, you can do this using a dynamic query:
DO $$
DECLARE
r record;
sql text;
i integer;
BEGIN
sql := 'SELECT * from records';
FOR i IN 1..5
LOOP
sql := sql || ' JOIN (SELECT * FROM records where records.id = ' || i || ')';
END LOOP;
RAISE INFO 'Query: %', sql;
EXECUTE sql;
END$$;
answered Nov 20 '18 at 19:55
Julia Leder
51127
add a comment |
More simply:
SELECT * from records where id BETWEEN 1 and 10;
If you're doing something more complex you could use generate_series to generate your 1..n ids (n = 10 in this example):
SELECT *
FROM records r
JOIN (SELECT generate_series(1, 10) id) s
ON r.id = s.id;
answered Nov 20 '18 at 21:39
teppic
5,16911826
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Yes, you can do this using a dynamic query:
DO $$
DECLARE
r record;
sql text;
i integer;
BEGIN
sql := 'SELECT * from records';
FOR i IN 1..5
LOOP
sql := sql || ' JOIN (SELECT * FROM records where records.id = ' || i || ')';
END LOOP;
RAISE INFO 'Query: %', sql;
EXECUTE sql;
END$$;
answered Nov 20 '18 at 19:55
Julia Leder
51127
add a comment |
Yes, you can do this using a dynamic query:
DO $$
DECLARE
r record;
sql text;
i integer;
BEGIN
sql := 'SELECT * from records';
FOR i IN 1..5
LOOP
sql := sql || ' JOIN (SELECT * FROM records where records.id = ' || i || ')';
END LOOP;
RAISE INFO 'Query: %', sql;
EXECUTE sql;
END$$;
answered Nov 20 '18 at 19:55
Julia Leder
51127
add a comment |
Yes, you can do this using a dynamic query:
DO $$
DECLARE
r record;
sql text;
i integer;
BEGIN
sql := 'SELECT * from records';
FOR i IN 1..5
LOOP
sql := sql || ' JOIN (SELECT * FROM records where records.id = ' || i || ')';
END LOOP;
RAISE INFO 'Query: %', sql;
EXECUTE sql;
END$$;
answered Nov 20 '18 at 19:55
Julia Leder
51127
Yes, you can do this using a dynamic query:
DO $$
DECLARE
r record;
sql text;
i integer;
BEGIN
sql := 'SELECT * from records';
FOR i IN 1..5
LOOP
sql := sql || ' JOIN (SELECT * FROM records where records.id = ' || i || ')';
END LOOP;
RAISE INFO 'Query: %', sql;
EXECUTE sql;
END$$;
answered Nov 20 '18 at 19:55
Julia Leder
51127
answered Nov 20 '18 at 19:55
Julia Leder
51127
answered Nov 20 '18 at 19:55
Julia Leder
51127
answered Nov 20 '18 at 19:55
Julia Leder
51127
51127
add a comment |
add a comment |
More simply:
SELECT * from records where id BETWEEN 1 and 10;
If you're doing something more complex you could use generate_series to generate your 1..n ids (n = 10 in this example):
SELECT *
FROM records r
JOIN (SELECT generate_series(1, 10) id) s
ON r.id = s.id;
answered Nov 20 '18 at 21:39
teppic
5,16911826
add a comment |
More simply:
SELECT * from records where id BETWEEN 1 and 10;
If you're doing something more complex you could use generate_series to generate your 1..n ids (n = 10 in this example):
SELECT *
FROM records r
JOIN (SELECT generate_series(1, 10) id) s
ON r.id = s.id;
answered Nov 20 '18 at 21:39
teppic
5,16911826
add a comment |
More simply:
SELECT * from records where id BETWEEN 1 and 10;
If you're doing something more complex you could use generate_series to generate your 1..n ids (n = 10 in this example):
SELECT *
FROM records r
JOIN (SELECT generate_series(1, 10) id) s
ON r.id = s.id;
answered Nov 20 '18 at 21:39
teppic
5,16911826
More simply:
SELECT * from records where id BETWEEN 1 and 10;
If you're doing something more complex you could use generate_series to generate your 1..n ids (n = 10 in this example):
SELECT *
FROM records r
JOIN (SELECT generate_series(1, 10) id) s
ON r.id = s.id;
answered Nov 20 '18 at 21:39
teppic
5,16911826
edited Nov 20 '18 at 21:45
answered Nov 20 '18 at 21:39
teppic
5,16911826
answered Nov 20 '18 at 21:39
teppic
5,16911826
answered Nov 20 '18 at 21:39
teppic
5,16911826
5,16911826
add a comment |
add a comment |
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Please Edit your question and add some sample data and the expected output based on that data. Formatted text please, no screen shots. edit your question - do not post code or additional information in comments.
– a_horse_with_no_name
Nov 20 '18 at 21:48