I have this table:
ID Value
------------
1 car
1 moto
2 car
2 moto
3 moto
3 apple
4 gel
4 moto
5 NULL
note that moto is common to all IDs.
I would to obtain a single row with this result
car*, moto, apple*, gel*
i.e.
car, apple, gel with an asterisk because is present but NOT in all IDs
moto without an asterisk because is COMMON to all IDs
If ID + Value are Unique
SELECT Value, CASE WHEN COUNT(*) <> (SELECT COUNT(DISTINCT ID) FROM MyTable) THEN '*' ELSE '' END AS Asterisk FROM MyTable WHERE Value IS NOT NULL GROUP BY Value
Note that this won't group in a single line. And note that your question is wrong. ID 5 is an ID, so moto isn't common to all the IDs. It's common to all the IDs that have at least a value.
If we filter these IDs as written,
SELECT Value, CASE WHEN COUNT(*) <> (SELECT COUNT(DISTINCT ID) FROM MyTable WHERE Value IS NOT NULL) THEN '*' ELSE '' END FROM MyTable WHERE Value IS NOT NULL GROUP BY Value
To "merge" the * with Value, simply replace the , with a +, like:
SELECT Value + CASE WHEN COUNT(*) <> (SELECT COUNT(DISTINCT ID) FROM MyTable WHERE Value IS NOT NULL) THEN '*' ELSE '' END Value FROM MyTable WHERE Value IS NOT NULL GROUP BY Value
To make a single line use one of https://www.simple-talk.com/sql/t-sql-programming/concatenating-row-values-in-transact-sql/ I'll add that, sadly, tsql doesn't have any native method to do it, and all the alternatives are a little ugly :-)
In general, the string aggregation part is quite common on SO (and outside of it) Concatenate row values T-SQL, tsql aggregate string for group by, Implode type function in SQL Server 2000?, How to return multiple values in one column (T-SQL)? and too many others to count :-)
Related
I have two tables, Users and Masters. Users are having User specific settingkey-value. Masters is having master settingkey-value. I want to display key-value from the two tables, where
if users do not have that particular key, need to take it from masters
2 if the users do not exists in the table, need to display all from masters key-value
if users having key-value, have to display users key-value
Example:
Inputs being - UserID and appID = 1.
I tried with left join combination, but not getting desired result if Users do not exists at all in the Users table.
Could you please give me some advise.
step-by-step demo:db<>fiddle
SELECT
COALESCE(m.app_id, u.app_id) as app_id,
COALESCE(m.setting_key, u.setting_key) as setting_key,
COALESCE(u.setting_value, m.setting_value) as setting_value -- 2
FROM
master_table m
FULL OUTER JOIN -- 1
user_table u
ON m.app_id = u.app_id AND m.setting_key = u.setting_key
WHERE COALESCE(m.app_id, u.app_id) = 1 -- 3
AND (u.user_id = 1 OR u.user_id IS NULL)
You need a FULL OUTER JOIN to join also data set that the other table does not contain
COALESCE(a, b) gives you the first non-null value. So, if a (here the user value) is available, it will be returned. Otherwise b (here the master value)
Filter by app_id and user_id; second needs to be filtered by user_id == NULL too, to get all setting_keys. Of course, you could use here COALESCE as well: COALESCE(u.user_id, 1) whereas the last 1 is the specific user_id you're asking
Edit: If User does not exist, give out the Masters values for app_id:
step-by-step demo:db<>fiddle:
SELECT DISTINCT ON (app_id, setting_key) -- 3
*
FROM (
SELECT
COALESCE(user_app_id, master_app_id) AS app_id, -- 2
COALESCE(user_setting_key, master_setting_key) AS setting_key,
COALESCE(user_setting_value, master_setting_value) AS setting_value,
user_id
FROM (
SELECT
app_id as master_app_id,
setting_key as master_setting_key,
setting_value as master_setting_value,
null as user_id,
null as user_app_id,
null as user_setting_key,
null as user_setting_value
FROM
master_table m
UNION -- 1
SELECT
*
FROM
master_table m
FULL OUTER JOIN
user_table u
ON m.app_id = u.app_id AND m.setting_key = u.setting_key
) s
) s
WHERE app_id = 1
AND (user_id = 2 OR user_id IS NULL)
ORDER BY app_id, setting_key, user_id NULLS LAST -- 3
This is a little more complicated. You need a separate data set for user_id == NULL which could be fetched. So, the NULL user represents the unknown user.
You can achieve this by adding the Master table with NULL values using an UNION.
Now you can create the expected columns with the COALESCE() functions as described above.
The third trick is using the DISTINCT ON clause on the app_id and the setting_key columns. When you ordered the NULL columns from the default UNION part in (1) last, then the DISTINCT ON will fetch the user record. However, when the user didn't exist, then the DISTINCT ON will fetch the default Master record.
I have some interesting data, I'm trying to query however I cannot get the syntax correct. I have a temporary table (temp_id), which I've filled with the id values I care about. In this example it is only two ids.
CREATE TEMPORARY TABLE temp_id (id bigint PRIMARY KEY);
INSERT INTO temp_id (id) VALUES ( 1 ), ( 2 );
I have another table in production (let's call it foo) which holds multiples those ids in a single cell. The ids column looks like this (below) with ids as a single string separated by "|"
ids
-----------
1|9|3|4|5
6|5|6|9|7
NULL
2|5|6|9|7
9|11|12|99
I want to evaluate each cell in foo.ids, and see if any of the ids in match the ones in my temp_id table.
Expected output
ids |does_match
-----------------------
1|9|3|4|5 |true
6|5|6|9|7 |false
NULL |false
2|5|6|9|7 |true
9|11|12|99 |false
So far I've come up with this, but I can't seem to return anything. Instead of trying to create a new column does_match I tried to filter within the WHERE statement. However, the issue is I cannot figure out how to evaluate all the id values in my temp table to the string blob full of the ids in foo.
SELECT
ids,
FROM foo
WHERE ids = ANY(SELECT LISTAGG(id, ' | ') FROM temp_ids)
Any suggestions would be helpful.
Cheers,
this would work, however not sure about performance
SELECT
ids
FROM foo
JOIN temp_ids
ON '|'||foo.ids||'|' LIKE '%|'||temp_ids.id::varchar||'|%'
you wrap the IDs list into a pair of additional separators, so you can always search for |id| including the first and the last number
The following SQL (I know it's a bit of a hack) returns exactly what you expect as an output, tested with your sample data, don't know how would it behave on your real data, try and let me know
with seq AS ( # create a sequence CTE to implement postgres' unnest
select 1 as i union all # assuming you have max 10 ids in ids field,
# feel free to modify this part
select 2 union all
select 3 union all
select 4 union all
select 5 union all
select 6 union all
select 7 union all
select 8 union all
select 9 union all
select 10)
select distinct ids,
case # since I can't do a max on a boolean field, used two cases
# for 1s and 0s and converted them to boolean
when max(case
when t.id in (
select split_part(ids,'|',seq.i) as tt
from seq
join foo f on seq.i <= REGEXP_COUNT(ids, '|') + 1
where tt != '' and k.ids = f.ids)
then 1
else 0
end) = 1
then true
else false
end as does_match
from temp_id t, foo
group by 1
Please let me know if this works for you!
I have table a, in this table after a SQL request, I have the same records a few times.
Here is my request.
for server_id in (select bs.id from status.servers bs
join settings.config blc on bs.id = blc.server_id
where blc.lane_number = (dataitem->>'No')::SMALLINT AND blc.min_length <= (dataitem->>'len')::real
)
LOOP
insert into a(measurement_id, server_id, status)
VALUES (
measurement_id,server_id,false
);
END LOOP;
And as result i have in table a, records like:
id meas_id serv_id status
1 12 1 f
2 12 1 f
3 12 1 f
i've changed code a little, in working code there are not syntax mistakes
answering
"why i have the same records with dif id?"
table a probably have a default value for column id, so values are taken from sequence. most probably you created it with serial data type... Those results are expected then. If you want to define your value, you should not skip column in scalar list, so
insert into a(measurement_id, server_id, status)
must become
insert into a(id, measurement_id, server_id, status)
and the value passed accordingly...
If you expected one result (assuming it from same value of server_id), you need to add distinct to the
for server_id in (select distinct bs.id from status.servers bs
because currently your select returns three rows with same bs.id as result of a join with three matching rows on join key...
For Postgresql 8.x, I have an answers table containing (id, user_id, question_id, choice) where choice is a string value. I need a query that will return a set of records (all columns returned) for all unique choice values. What I'm looking for is a single representative record for each unique choice. I also want to have an aggregate votes column that is a count() of the number of records matching each unique choice accompanying each record. I want to force choice to lowercase for this comparison to be made (HeLLo and Hello should be considered equal). I can't GROUP BY lower(choice) because I want all columns in the result-set. Grouping by all columns causes all records to return, including all duplicates.
1. Closest I've gotten
select lower(choice), count(choice) as votes from answers where question_id = 21 group by lower(choice) order by votes desc;
The issue with this is it will not return all columns.
lower | votes
-----------------------------------------------+-------
dancing in the moonlight | 8
pumped up kicks | 7
party rock anthem | 6
sexy and i know it | 5
moves like jagger | 4
2. Trying with all columns
select *, count(choice) as votes from answers where question_id = 21 group by lower(choice) order by votes desc;
Because I am not specifying every column from the SELECT in my GROUP BY, this throws an error telling me to do so.
3. Specifying all columns in the GROUP BY
select *, count(choice) as votes from answers where question_id = 21 group by lower(choice), id, user_id, question_id, choice order by votes desc;
This simply dumps the table with votes column as 1 for all records.
How can I get the vote count and unique representative records from 1., but with all columns from the table returned?
Join grouped results back with primary table, then show only one row for each (question,answer) combination.
similar to this:
WITH top5 AS (
select question_id, lower(choice) as choice, count(*) as votes
from answers
where question_id = 21
group by question_id , lower(choice)
order by count(*) desc
limit 5
)
SELECT DISTINCT ON(question_id,choice) *
FROM top5
JOIN answers USING(question_id,lower(choice))
ORDER BY question_id, lower(choice), answers.id;
Here's what I ended up with:
SELECT answers.*, cc.votes as votes FROM answers join (
select max(id) as id, count(id) as votes
from answers
group by trim(lower(choice))
) cc
on answers.id = cc.id ORDER BY votes desc, lower(response) asc
Currently I've a query as follows:
-- Query 1
SELECT
acc_code, acc_name, alias, LAmt, coalesce(LAmt,0) AS amt
FROM
(SELECT
acc_code, acc_name, alias,
(SELECT
(SUM(cr_amt)-SUM(dr_amt))
FROM
ledger_mcg l
WHERE
(l.acc_code LIKE a.acc_code + '.%' OR l.acc_code=a.acc_code)
AND
fy_id=1
AND
posted_date BETWEEN '2010-01-01' AND '2011-06-02') AS LAmt
FROM
acc_head_mcg AS a
WHERE
(acc_type='4')) AS T1
WHERE
coalesce(LAmt,0)<>0
Query 2 is same as Query 1 except that acc_type = '5' in Query 2. Query 2 always returns a resultset with a single row. Now, I need the union of the two queries i.e
Query 1
UNION
Query 2
only when the amt returned by Query 2 is less than 0. Else, I don't need a union but only the resulset from Query 1.
The best way I can think of is to create a parameterised scalar function. How best can I do this?
You could store the result of the first query into a temporary table, then, if the table wasn't empty, execute the other query.
IF OBJECT_ID('tempdb..#MultipleQueriesResults') IS NOT NULL
DROP TABLE #MultipleQueriesResults;
SELECT
acc_code, acc_name, alias, LAmt, coalesce(LAmt,0) AS amt
INTO #MultipleQueriesResults
FROM
(SELECT
acc_code, acc_name, alias,
(SELECT
(SUM(cr_amt)-SUM(dr_amt))
FROM
ledger_mcg l
WHERE
(l.acc_code LIKE a.acc_code + '.%' OR l.acc_code=a.acc_code)
AND
fy_id=1
AND
posted_date BETWEEN '2010-01-01' AND '2011-06-02') AS LAmt
FROM
acc_head_mcg AS a
WHERE
(acc_type='4')) AS T1
WHERE
coalesce(LAmt,0)<>0;
IF NOT EXISTS (SELECT * FROM #MultipleQueriesResults)
… /* run Query 2 */