How come this does not work and what is a workaround?
DELETE FROM
(SELECT
PKID
, a
, b)
Where a > 1
There is a Syntax Error at "(".
DELETE FROM (TABLE) where a > 1 gives the same syntax error.
I need to delete specific rows that are flagged using a rank function in my select statement.
I have now put a table immediately after the DELETE FROM and put WHERE restrictions on the DELETE and in a small series of self-joins of the table.
DELETE FROM TABLE1
WHERE x IN
(SELECT A.x
FROM (SELECT x, r1.y, r2.y, DENSE_RANK() OVER (PARTITION by r1.y, r2.y ORDER by x) AS RANK
FROM TABLE2 r0
INNER JOIN TABLE1 r1 on r0.x = r1.x
INNER JOIN TABLE1 r2 on r0.x = r2.x
WHERE r1.y = foo and r2.y = bar
) AS A
WHERE A.RANK > 1
)
Related
I am facing an error in snowflake saying "Unsupported subquery type cannot be evaluated" after for example executing the below statement. How should write this statement to avoid this error?
select A
from (
select b
, c
FROM test_table
) ;
The outer query column list needs to be within the column list of the subquery. example: select b from (select b,c from test_table);
ignoring "columns" the query you have shown will never trigger this error.
You would get it from this form though:
select A.*
from tableA as A
where a.x = (select b.y FROM test_table as b where b.z = a.z)
this form assuming there is only 1 b.y per b.z can be turned into a inner join like
select A.*
from tableA as A
join test_table as b
on b.z = a.z and a.x = b.y
other forms of this pattern do the likes of max(b.y) and those can be made into a sub-select like:
select A.*
from tableA as A
join (
select c.z, max(c.y) from test_table as c group by 1
) as b
on b.z = a.z and a.x = b.y
but the general pattern is, in other databases there is no "cost" to do row-by-row queries, where-as Snowflake is more optimal with pre-building tables of similar data, and then equi-joining those results together. So both the "how-to-write" example pivot from a for-each-row thinking to a build the set of all possible answers, and then join that. This allows for the most parallel processing of the data possible. And while it means you the develop need to understand your data to get he best performance out of it, in general if you are doing large scale data processing, you should be understanding your data. So this costs, is rather acceptable imho.
If you are trying to Match Two Attributes on the Subquery.
Use like below:
If both need to matched:
select * from Table WHERE a IN ( select b FROM test_table ) AND a IN ( select c FROM test_table )
If any one need to matched:
select * from Table WHERE a IN ( select b FROM test_table ) OR a IN ( select c FROM test_table )
I got two tables below:
And I want to create a query to combine them like below:
But unsuccessfully I got something like this:
Some data for "value1" duplicated
How can I solve this?
Is there any function that can have "value1" for the first "no." only?
Thank you.
You can do this by using a subquery to prepare the data.
It seems you want only the rows with the lowest Sub no to join, so we'll first select that:
SELECT [No], Value2
FROM Table2 m
WHERE
EXISTS(
SELECT 1
FROM Table2 s
WHERE s.[No] = m.[No]
HAVING MIN(s.sub_no) = m.sub_no
)
Then, integrate this into your main query:
SELECT *
FROM Table1
INNER JOIN (
SELECT [No], Value2
FROM Table2 m
WHERE
EXISTS(
SELECT 1
FROM Table2 s
WHERE s.[No] = m.[No]
HAVING MIN(s.sub_no) = m.sub_no
)
) AS T2 ON T1.[No] = T2.[No]
I have query select col1, col2 from view1 and I wanted execute only when (select columnvalue from table1) > 0 else do nothing.
if (select columnvalue from table1)>0
select col1, col2 from view1"
else
do thing
How can I achieve this in single hive query?
If check query returns scalar value (single row) then you can cross join with check result and filter using > 0 condition:
with check_query as (
select count (*) cnt
from table1
)
select *
from view1 t
cross join check_query c
where c.cnt>0
;
I'm working on a WinForms application with an Access database.
Please correct me.
Select *
from EMP
where Empid in
(Select id
from Test1
where pin=4
UNION
Select id
from Test2
where pin=4)
When I try to execute this on the Access database, it gave me this error:
Operations are not allowed in subquery
You can also use two standard SQL where conditions, as per below. I have tested this approach and it appears to work as expected
SELECT x, y, z
WHERE x NOT IN (SELECT x FROM b)
AND NOT IN (SELECT x FROM c)
I tried as below and its worked.
Select *
from EMP where Empid in (Select id from Test1 where pin=4 ) UNION
Select *
from EMP where Empid in(Select id from Test2 where pin=4)
Really late but this works
Select *
from EMP
where Empid in
(SELECT id FROM (
Select id from Test1 where pin=4
UNION Select id from Test2 where pin=4 ) )
How about something like
Select e.*
from EMP e INNER JOIN
(
Select id
from Test1
where pin=4
UNION
Select id
from Test2
where pin=4
) subSelect ON e.Empid = subSelect.id
as far as i know union operations are not allowed in subqueries,instead you can create a named union query and include in the subquery expression
SELECT BabyInformation.* , t1.*
FROM BabyInformation
LEFT JOIN
(SELECT * FROM BabyData
GROUP BY BabyID
ORDER By Date DESC ) AS t1 ON BabyInformation.BabyID=t1.BabyID
This is my query. I want to get the one most recent BabyData tuple based on date.
The BabyInformation should left join with babyData but one row per baby...
I tried TOP(1) but this worked only for the first baby
Here is one way to do it, there are other ways which can be faster, but I believe this one to be the clearest for a beginner.
SELECT BabyInformation.*, BabyData.*
FROM BabyInformation
JOIN
(SELECT BabyID, Max(Date) as maxDate FROM BabyData
GROUP BY BabyID
) AS t1
ON BabyInformation.BabyID=t1.BabyID
Join BabyData ON BabyData.BabyID = t1.BabyID and BabyData.Date = t1.maxDate
This should do it:
SELECT bi.* , bd.*
FROM BabyInformation [bi]
LEFT JOIN BabyData [bd]
on bd.BabyDataId = (select top 1 sub.BabyDataId from BabyData [sub] where sub.BabyId = bi.BabyId order by sub.Date desc)
I've assumed that there is a column called 'BabyDataId' in the BabyData table.