I have a list of IDs
'ACE', 'ACD', 'IDs', 'IN','CD'
I also have a table similar to following structure
ID value
ACE 2
CED 3
ACD 4
IN 4
IN 4
I want a SQL query that returns a list of IDs that exists in the database and a list of IDs that does not in the database.
The return should be:
1.ACE, ACD, IN (exist)
2.IDs,CD (not exist)
my code is like this
select
ID,
value
from db
where ID is in ( 'ACE', 'ACD', 'IDs', 'IN','CD')
however, the return is 1) super slow with all kinds of IDs 2) return multiple rows with the same ID. Is there anyway using postgresql to return 1) unique ID 2) make the running faster?
Assuming no duplicates in table nor input, this query should do it:
SELECT t.id IS NOT NULL AS id_exists
, array_agg(ids.id)
FROM unnest(ARRAY['ACE','ACD','IDs','IN','CD']) ids(id)
LEFT JOIN tbl t USING (id)
GROUP BY 1;
Else, please define how to deal with duplicates on either side.
If the LEFT JOIN finds a matching row, the expression t.id IS NOT NULL is true. Else it's false. GROUP BY 1 groups by this expression (1st in the SELECT list), array_agg() forms arrays for each of the two groups.
Related:
Select rows which are not present in other table
Hmmm . . . Is this sufficient:
select ids.id,
(exists (select 1 from table t where t.id = ids.id)
from unnest(array['ACE', 'ACD', 'IDs', 'IN','CD']) ids(id);
Related
I have the following query which works great but how do I add multiple columns in its select statement? Following is the query:
SELECT ISNULL(
(SELECT DISTINCT a.DatasourceID
FROM [Table1] a
WHERE a.DatasourceID = 5 AND a.AgencyID = 4 AND a.AccountingMonth = 201907), NULL) TEST
So currently I only get one column (TEST) but would like to add other columns such as DataSourceID, AgencyID and AccountingMonth.
If you want to output a row for some condition (or requested values ) and output a row when it does not meet condition,
you can set a pseudo table for your requested values in the FROM clause and make a left outer join with your Table1.
SELECT ISNULL(Table1.DatasourceId, 999999),
Table1.AgencyId,
Table1.AccountingMonth,
COUNT(*) as count
FROM ( VALUES (5, 4, 201907 ),
(6, 4, 201907 ))
AS requested(DatasourceId, AgencyId, AccountingMonth)
LEFT OUTER JOIN Table1 ON requested.agencyid=Table1.AgencyId
AND requested.datasourceid = Table1.DatasourceId
AND requested.AccountingMonth = Table1.AccountingMonth
GROUP BY Table1.DatasourceId, Table1.AgencyId, Table1.AccountingMonth
Note that:
I have put a ISNULL for the first column like you did to output a particular value (9999) when no value is found.
I did not put the ISNULL(...,NULL) like your query in the other columns since IMHO it is not necessary: if there is no value, a null will be output anyway.
I added a COUNT(*) column to illustrate an aggregate, you could use another (SUM, MIN, MAX) or none if you do not need it.
The set of requested values is provided as a constant table values (see https://learn.microsoft.com/en-us/sql/t-sql/queries/table-value-constructor-transact-sql?view=sql-server-2017)
I have added multiple rows for requested conditions : you can request for multiple datasources, agencies or months in one query with one line for each in the output.
If you want only one row, put only one row in "requested" pseudo table values.
There must be a GROUP BY, even if you do not want to use an aggregate (count, sum or other) in order to have the same behavior as your distinct clause , it restricts the output to single lines for requested values.
To me it seems that you want to see does data exists, i guess that your's AgencyID is foreign key to agency table, DataSourceID also to DataSource, and that you have AccountingMonth table which has all accounting periods:
SELECT ds.ID as DataSourceID , ag.ID as AgencyID , am.ID as AccountingMonth ,
ISNULL(COUNT(a.*),0) as Count
FROM [Table1] a
RIGHT JOIN [Datasource] ds ON ds.ID = a.DataSourceID
RIGHT JOIN [Agency] ag ON ag.ID = a.AgencyID
RIGHT JOIN [AccountingMonth] am on am.ID = a.AccountingMonth
GROUP BY ds.ID, ag.ID, am.ID
In this way you can see count of records per group by criteria. Notice RIGHT join, you must use RIGHT JOIN if you want to include all record from "Right" table.
In yours query you have DISTINCT a.DatasourceID and WHERE a.DatasourceID = 5 and it returns 5 if in table exists rows that match yours WHERE criteria, and returns null if there is no data. If you remove WHERE a.DatasourceID = 5 your query would break with error: subquery returned multiple rows.
the way you are doing only allows for one column and one record and giving it the name of test. It does not look like you really need to test for null. because you are returning null so that does nothing to help you. Remove all the null testing and return a full recordset distinct will also limit your returns to 1 record. When working with a single table you don't need an alias, if there are no spaces or keywords braced identifiers not required. if you need to see if you have an empty record set, test for it in the calling program.
SELECT DatasourceID, AgencyID,AccountingMonth
FROM Table1
WHERE DatasourceID = 5 AND AgencyID = 4 AND AccountingMonth = 201907
(P.S. I am still learning SQL and you can consider me a newbie)
I have 2 sample tables as follows:
Table 1
|Profile_ID| |Img_Path|
Table 2
|Profile_ID| |UName| |Default_Title|
My scenario is, from the 2nd table, i need to fetch all the records that contain a certain word, for which i have the following query :
Select Profile_Id,UName from
Table2 Where
Contains(Default_Title, 'Test')
ORDER BY Profile_Id
OFFSET 5 ROWS
FETCH NEXT 20 ROWS ONLY
(Note that i am setting the OFFSET due to requirements.)
Now, the scenario is, as soon as i retrieve 1 record from the 2nd table, i need to fetch the record from the 1st table based on the Profile_Id.
So, i need to return the following 2 results in one single statement :
|Profile_Id| |Img_Path|
|Profile_Id| |UName|
And i need to return the results in side-by-side columns, like :
|Profile_Id| |Img_Path| |UName|
(Note i had to merge 2 Profile_Id columns into one as they both contain same data)
I am still learning SQL and i am learning about Union, Join etc. but i am a bit confused as to which way to go.
You can use join:
select t1.*, t2.UName
from table1 t1 join
(select Profile_Id, UName
from Table2
where Contains(Default_Title, 'Test')
order by Profile_Id
offset 5 rows fetch next 20 rows only
) t2
on t2.profile_id = t1.profile_id
SELECT a.Profile_Id, a.Img_Path, b.UName
FROM table1 a INNER JOIN table2 b ON a.Profile_Id=b.Profile_Id
WHERE b.Default_Title = 'Test'
I am running the following (Postgres) SQL against a table containing a list of ids. The SQL below will return all the ids found in the list* below.
select id from table
where id in (1,2,3,5,8,11,13,22,34,55);
How can I return ids which are contained in the list but not in the table? I realise I can do this using a temp table (with the list in it) and a left outer join but is there a quicker/cleverer way?
To check if arbitrary ids exist in your table, use a CTE and exists
WITH ids (id) AS ( VALUES (1),(2),(3),(5),(8),(11),(13),(22),(34),(55)
)
SELECT id
FROM ids
WHERE NOT EXISTS(SELECT TRUE FROM table WHERE table.id = ids.id)
note1: alternatively use a left join instead of WHERE NOT EXISTS
note2: it may be necessary to add the appropriate type casts
Or you can use EXCEPT
WITH ids (id) AS ( VALUES (1),(2),(3),(5),(8),(11),(13),(22),(34),(55)
)
SELECT id
FROM ids
EXCEPT ALL
SELECT id FROM ids
I have two columns id and segment. Segment is comma separated set of strings. I need to find average number of segments in all the table. One way to do it is by using two separate queries -
A - select count(*) from table_name;
B - select count(*) from table_name LATERAL VIEW explode(split(segment, ',') lTable AS singleSegment where segment != ""
avg = B/A
Answer would be 8/4 = 2 in the above case.
Is there a better way to achieve this ?
Try:
select sum(CASE segment
WHEN '' THEN 0
ELSE size(split(segment,','))
END
)*1.0/count(*) from table_name;
If your id field is unique, and you want to add a filter to the segment part, or protect against other malformed segment values like a,b, and a,,b, you could do:
SELECT SUM(seg_size)*1.0/count(*) FROM (
SELECT count(*) as seg_size from table_name
LATERAL VIEW explode(split(segment, ',')) lTable AS singleSegment
WHERE trim(singleSegment) != ""
GROUP BY id
) sizes
Then you can add other stuff into the where clause.
But this query takes two Hive jobs to run, compared to one for the simpler query, and requires the id field to be unique.
I have a table table and I'm trying to show all the rows with the id in a certain list. If there are no rows with this id, then I would display null values.
Obviously, if these ids I want to select were in a different table, then the solution was just a right join statement.
The problem is that such table does not exists and the user provides the list of ids as input.
I'm trying to solve this using the right join (values ..) on ..=.. statement. But I'm unable to give a column name to the nested statement (with static values). And so I'm unable to write a valid on clause.
For instance, I have the table table:
id val
-- --
0 0.1
2 -0.5
7 1.1
Then the user dinamically select a list of ids, which is not necessary contained in the list of ids of the table. For instance, if the user select 0,1,2,3, then I should diplay:
id val
-- --
0 0.1
1 null
2 -0.5
3 null
I'm trying to do something like
select * from table right outer join (
values (0),(1),(2),(3)
) as static_values on table.id = static_values[1]
Obviosuly static_values[1] is wrong, but I have to name the column to perform a join and I don't know how else to do it.
You should be able to do:
select *
from table
right outer join (values (0),(1),(2),(3)) as static_values(id)
on table.id = static_values.id