I have a scenario where i have to check a variable for it's default value, and if it has i have to check EXISTS part conditionally with Table2 and if it does not have the default value, i have to check EXISTS part conditionally with Table3.
Below is a sample code:-
SELECT * FROM tbl1 WHERE EXISTS (SELECT CASE WHEN #boolVar = 0 THEN (SELECT 'X' FROM tbl2 WHERE tbl1.col1 = tbl2.col1) ELSE (SELECT 'X' FROM tbl3 where tbl1.col1 = tbl3.col1) END)
Demo query with constants for testing purpose: -
SELECT 1 WHERE EXISTS (SELECT CASE WHEN 1 = 0 THEN (SELECT 'X' WHERE 1=0)
ELSE (SELECT 'X' WHERE 1 = 2) END)
Note: - The above query always returning 1, even not a single condition is satisfying.
I know we can use OR operator for the same and any how we can achieve it, but i really want to know that in case both the tables have no rows satisfying their particular where clause, even it's returning all the rows from Table1.
I tried to explain the same with the demo query with constant values.
Please help.
When your query doesn't find any matching records, it will basically do:
SELECT 1 WHERE EXISTS (SELECT NULL)
As a row containing a null value is still a row, the EXISTS command returns true.
You can add a condition to filter out the null row:
SELECT * FROM tbl1 WHERE EXISTS (
SELECT 1 FROM (
SELECT
CASE WHEN #boolVar = 0 THEN (SELECT 'X' FROM tbl2 WHERE tbl1.col1 = tbl2.col1)
ELSE (SELECT 'X' FROM tbl3 where tbl1.col1 = tbl3.col1)
END AS Y
) Z
WHERE Y IS NOT NULL
)
Here's an alternative, just in case:
SELECT *
FROM Table1
WHERE EXISTS (
SELECT 1
FROM Table2
WHERE #var = #defValue
AND ... /* other conditions as necessary */
UNION ALL
SELECT 1
FROM Table3
WHERE #var <> #defValue
AND ... /* other conditions as necessary */
);
Related
I have following query, which is working as expected but taking approx 3 seconds to execute. Reason is large number of records. Can somebody please suggest any steps in order to improve performance?
Explanation :
Check to see value using Comp id and Default_Comp = 1
If not found, ignore the Default_Comp and check only based on Comp id
Still not found, ignore the join with table 2 and try to get by Comp id.
My code:
DECLARE #Finished_Comp VARCHAR(MAX) = NULL;
SELECT #Finished_Comp = MIN(tbl2.Finished_Comp)
FROM Table1 tbl1
INNER JOIN Table2 tbl2 ON tbl1.Sav_ID = tbl2.Sav_ID
WHERE Comp_ID = #Comp_ID AND tbl1.Default_Comp = 1
IF #Finished_Comp IS NULL
BEGIN
SELECT #Finished_Comp = MIN(tbl2.Finished_Comp)
FROM Table1 tbl1
INNER JOIN Table2 tbl2 ON tbl1.Sav_ID = tbl2.Sav_ID
WHERE Comp_ID = #Comp_ID
END
IF #Finished_Comp IS NULL
BEGIN
SELECT #Finished_Comp = MIN(Finished_Comp)
FROM Table1 tbl1
WHERE Comp_ID = #Comp_ID AND #Finished_Comp != ''
END
I tried to use COALESCE, but it's returning wrong results for Finished_Comp
You say in the comments
I strongly believe the query can be changed to some extent so that no
multiple queries need to be executed.
Yes you're right.
SELECT #Finished_Comp = COALESCE(MIN(CASE WHEN tbl1.Default_Comp = 1 THEN tbl2.Finished_Comp END),
MIN(tbl2.Finished_Comp),
MIN(CASE WHEN tbl1.Finished_Comp <> '' THEN tbl1.Finished_Comp END))
FROM Table1 tbl1
LEFT JOIN Table2 tbl2
ON tbl1.Sav_ID = tbl2.Sav_ID
WHERE tbl1.Comp_ID = #Comp_IDV
But at best this will only reduce execution time to a third of current (for the case that all three queries need to be executed).
You should consider adding indexes on
Table1 - Comp_ID, Sav_ID INCLUDE (Default_Comp, Finished_Comp)
Table2 - Sav_ID INCLUDE (Finished_Comp)
For potentially much larger improvements.
First when I started this project seemed very simple. Two tables, field tbl1_USERMASTERID in Table 1 should be update from field tbl2_USERMASTERID Table 2. After I looked deeply in Table 2, there is no unique ID that I can use as a key to join these two tables. Only way to match the records from Table 1 and Table 2 is based on FIRST_NAME, LAST_NAME AND DOB. So I have to find records in Table 1 where:
tbl1_FIRST_NAME equals tbl2_FIRST_NAME
AND
tbl1_LAST_NAME equals tbl2_LAST_NAME
AND
tbl1_DOB equals tbl2_DOB
and then update USERMASTERID field. I was afraid that this can cause some duplicates and some users will end up with USERMASTERID that does not belong to them. So if I find more than one record based on first,last name and dob those records would not be updated. I would like just to skip and leave them blank. That way I wouldn't populate invalid USERMASTERID. I'm not sure what is the best way to approach this problem, should I use SQL or ColdFusion (my server side language)? Also how to detect more than one matching record?
Here is what I have so far:
UPDATE Table1 AS tbl1
LEFT OUTER JOIN Table2 AS tbl2
ON tbl1.dob = tbl2.dob
AND tbl1.fname = tbl2.fname
AND tbl1.lname = tbl2.lname
SET tbl1.usermasterid = tbl2.usermasterid
WHERE LTRIM(RTRIM(tbl1.usermasterid)) = ''
Here is query where I tried to detect duplicates:
SELECT DISTINCT
tbl1.FName,
tbl1.LName,
tbl1.dob,
COUNT(*) AS count
FROM Table1 AS tbl1
LEFT OUTER JOIN Table2 AS tbl2
ON tbl1.dob = tbl2.dob
AND tbl1.FName = tbl2.first
AND tbl1.LName = tbl2.last
WHERE LTRIM(RTRIM(tbl1.usermasterid)) = ''
AND LTRIM(RTRIM(tbl1.first)) <> ''
AND LTRIM(RTRIM(tbl1.last)) <> ''
AND LTRIM(RTRIM(tbl1.dob)) <> ''
GROUP BY tbl1.FName,tbl1.LName,tbl1.dob
Some data after I tested query above:
First Last DOB Count
John Cook 2008-07-11 2
Kate Witt 2013-06-05 1
Deb Ruis 2016-01-22 1
Mike Bennet 2007-01-15 1
Kristy Cruz 1997-10-20 1
Colin Jones 2011-10-13 1
Kevin Smith 2010-02-24 1
Corey Bruce 2008-04-11 1
Shawn Maiers 2016-08-28 1
Alenn Fitchner 1998-05-17 1
If anyone have idea how I can prevent/skip updating duplicate records or how to improve this query please let me know. Thank you.
You could check for and avoid duplicate matches using with common_table_expression (Transact-SQL)
along with row_number()., like so:
with cte as (
select
t.fname
, t.lname
, t.dob
, t.usermasterid
, NewUserMasterId = t2.usermasterid
, rn = row_number() over (partition by t.fname, t.lname, t.dob order by t2.usermasterid)
from table1 as t
inner join table2 as t2 on t.dob = t2.dob
and t.fname = t2.fname
and t.lname = t2.lname
and ltrim(rtrim(t.usermasterid)) = ''
)
--/* confirm these are the rows you want updated
select *
from cte as t
where t.NewUserMasterId != ''
and not exists (
select 1
from cte as i
where t.dob = i.dob
and t.fname = i.fname
and t.lname = i.lname
and i.rn>1
);
--*/
/* update those where only 1 usermasterid matches this record
update t
set t.usermasterid = t.NewUserMasterId
from cte as t
where t.NewUserMasterId != ''
and not exists (
select 1
from cte as i
where t.dob = i.dob
and t.fname = i.fname
and t.lname = i.lname
and i.rn>1
);
--*/
I use the cte to extract out the sub query for readability. Per the documentation, a common table expression (cte):
Specifies a temporary named result set, known as a common table expression (CTE). This is derived from a simple query and defined within the execution scope of a single SELECT, INSERT, UPDATE, or DELETE statement.
Using row_number() to assign a number for each row, starting at 1 for each partition of t.fname, t.lname, t.dob. Having those numbered allows us to check for the existence of duplicates with the not exists() clause with ... and i.rn>1
You could use a CTE to filter out the duplicates from Table1 before joining:
; with CTE as (select *
, count(ID) over (partition by LastName, FirstName, DoB) as IDs
from Table1)
update a
set a.ID = b.ID
from Table2 a
left join CTE b
on a.FirstName = b.FirstName
and a.LastName = b.LastName
and a.Dob = b.Dob
and b.IDs = 1
This will work provided there are no exact duplicates (same demographics and same ID) in table 1. If there are exact duplicates, they will also be excluded from the join, but you can filter them out before the CTE to avoid this.
Please try below SQL:
UPDATE Table1 AS tbl1
INNER JOIN Table2 AS tbl2
ON tbl1.dob = tbl2.dob
AND tbl1.fname = tbl2.fname
AND tbl1.lname = tbl2.lname
LEFT JOIN Table2 AS tbl3
ON tbl3.dob = tbl2.dob
AND tbl3.fname = tbl2.fname
AND tbl3.lname = tbl2.lname
AND tbl3.usermasterid <> tbl2.usermasterid
SET tbl1.usermasterid = tbl2.usermasterid
WHERE LTRIM(RTRIM(tbl1.usermasterid)) = ''
AND tbl3.usermasterid is null
I have the following table:
column1 column2 column3
3 2 0
5 9 2
1 4 6
When I run the following code:
SELECT
id_function = #param,
MIN(t1.column1) AS c1min,
MAX(t1.column2) AS c2max,
MIN(t1.column3) AS c3min
FROM
table1 (NOLOCK) AS t1
WHERE
t1.id = #param
I get:
c1min c2max c3min
1 9 0
My problem is that c3min must be the minimum value greater than zero.
The result I need should be:
c1min c2max c3min
1 9 2
Is there any way to do that without using a subselect?
Any help will be appreciated.
Thank you!
I would recommend using nullif() so your query would be
SELECT id_function = #param,
MIN(t1.column1) AS c1min,
MAX(t1.column2) AS c2max,
MIN(NULLIF(t1.column3,0) AS c3min
FROM table1 (NOLOCK) AS t1
WHERE t1.id = #param
that way you don't risk altering your results, e.g. if your real minimum in column 3 is 100 the previous answer would affect your results, and also if you only have zeros in your column 3 column the previous answer would also deliver incorrect results
You could use a case to set the 0 value to a higher value on your min() condition
SELECT id_function = #param,
MIN(t1.column1) AS c1min,
MAX(t1.column2) AS c2max,
MIN(case when t1.column3 = 0 then 99 else t1.column3 end) AS c3min
FROM table1 (NOLOCK) AS t1
WHERE t1.id = #param
It work .
(But I thing answer of :Hedinn is best answer ).
SELECT id_function = #param ,
c1min = ( SELECT MIN(t1Sub.column1)
FROM table1 (NOLOCK) AS t1Sub
WHERE t1Sub.id = #param
) ,
c2max = ( SELECT MAX(t2Sub.column2)
FROM table1 (NOLOCK) AS t2Sub
WHERE t2Sub.id = #param
) ,
c3min = ( SELECT MIN(t3Sub.column3)
FROM table1 (NOLOCK) AS t3Sub
WHERE ( t3Sub.id = #param )
AND ( t3Sub.column3 <> 0 )
)
FROM table1 (NOLOCK) AS t1
WHERE ( t1.id = #param )
I have 2 Excel files which I imported into MS Access as two tables. These two tables are identical but imported on different dates.
Now, how can I find out what rows and what fields are updated on the later date? Any help would be highly appreciated.
Finding Inserted records is easy
select * from B where not exists (select 1 from A where A.pk=B.pk)
Finding Deleted records is just as easy
select * from A where not exists (select 1 from B where A.pk=B.pk)
Finding Updated records is a pain. The following rigorous query assumes you have nullable columns and it should work in all situations.
select B.*
from B
inner join A on B.pk=A.pk
where A.col1<>B.col1 or (IsNull(A.col1) and not IsNull(B.col1)) or (not IsNull(A.col1) and IsNull(B.col1))
or A.col2<>B.col2 or (IsNull(A.col2) and not IsNull(B.col2)) or (not IsNull(A.col2) and IsNull(B.col2))
or A.col3<>B.col3 or (IsNull(A.col3) and not IsNull(B.col3)) or (not IsNull(A.col3) and IsNull(B.col3))
etc...
If the columns are defined as NOT NULL then the query is much simper, just remove all the NULL tests.
If the columns are nullable but you can identify a value that will never appear in the data, then use a simple comparison like:
Nz(A.col1,neverAppearingValue)<>Nz(B.col1,neverAppearingValue)
I believe this should be as simple as running a query like this:
SELECT *
FROM Table1
JOIN Table2
ON Table1.ID = Table2.ID AND Table1.Date != Table2.Date
One way to do this is by unpivoting both tables, so you get a new table with , , . Note, though, that you have to take types into account.
For example, the following gets differences in fields:
with oldt as (select id, col, val
from <old table> t
unpivot (val for col in (<column list>)) unpvt
),
newt as (select id, col, val
from <new table> t
unpivot (val for col in (<column list>)) unpvit
)
select *
from oldt full outer join newt on oldt.id = newt.id
where oldt.id is null or newt.id is null
The alternative way with a join is rather cumbersome. This version shows whether columns are added, deleted, and which columns changed if any:
select *
from (select coalesce(oldt.id, newt.id) as id,
(case when oldt.id is null and newt.id is not null then 'ADDED'
when oldt.id is not null and newt.id is null then 'DELETED'
else 'SAME'
end) as stat,
(case when oldt.col1 <> newt.col1 or oldt.col1 is null and newt.col1 is null
then 1 else 0 end) as diff_col1,
(case when oldt.col2 <> newt.col2 or oldt.col2 is null and newt.col2 is null
then 1 else 0 end) as diff_col2,
...
from <old table> oldt full outer join <new table> newt on oldt.id = newt.id
) c
where status in ('ADDED', 'DELETED') or
(diff_col1 + diff_col2 + ... ) > 0
It does have the advantage of working for any data types.
(Select * from OldTable Except Select *from NewTable)
Union All
(Select * from NewTable Except Select *from OldTable)
I have a feeling once i see the solution i'll slap my forehead, but right now I'm not seeing it.
I have a lookup table, say TableB, which looks like this. All fields are INT except the last two which are BOOL.
ID, TableA_ID, Value, Required, Disqualifies
I have a list of TableA_Id values (1, 2, 3 ) etc
For each record in this table, either Required can be true or disqualified can be true - they cant both be true at the same time. They can both be false or null though. There can be duplicate values of TableA_Id but there should never be duplicates of TableA_Id and Value
If required is true for any of those TableA_ID values, and none of those values are in my list, return no records. If none of the values are marked as required (required = 0 or null) then return records UNLESS any of the values are marked as Disqualifies and are in the list, in which case i want to return no records.
So - if a field is required and i dont have it, dont return any records. If a field is marked as disqualified and i have it, don't return any records. Only return a record if either i have a required value or don't have a disqualified value or there are no required values.
I hope I explained myself clearly.
Thanks in advance for pointing me in the right direction.
As an example of what my records might look like:
ID TableA_ID Value Required Disqualifies
-- --------- ----- -------- ------------
1 123 1 True False
2 123 2 True False
3 123 3 False False
4 123 4 False True
5 456 1 False True
6 456 2 False False
Given this set of sample data, if we're working with TableA_Id 123 and my list of values is lets say 1 and 3, i would get data returned because i have a required value and dont have any disqualified values. If my list of values were just 3, i'd get no records since i'm missing of the Required values. If my list of values were 1 and 4, i'd get no records because 4 is marked as disqualified.
Now if we're working with TableA_Id 456, the only list of values that would return any records is 2.
Maybe i should post the whole SQL query - i was trying to keep this short to make it easier for everyone, but it looks like maybe that's not working so well.
Here is the full dynamically generated query. The bit i am working on now is the 2nd line from the bottom. To equate this to my example, t.id would be TableA_ID, Value would be PDT_ID.
SELECT DISTINCT t.ID, t.BriefTitle, stat.Status, lstat.Status AS LocationStatus, st.SType, t.LAgency, l.City, state.StateCode
,( SELECT TOP 1 UserID
FROM TRecruiter
WHERE TrialID = t.ID AND Lead = 1 ), l.ID as LocationID
, l.WebBased
FROM Trial t
INNER JOIN Location l ON t.ID = l.TrialID
FULL JOIN pdt on t.ID = pdt.trialid
FULL JOIN pdm on t.ID = pdm.TrialID
FULL JOIN s on t.ID = s.TrialID
FULL JOIN hy on t.ID = hy.TrialID
FULL JOIN ta on t.ID = ta.TrialID
FULL JOIN stt on t.ID = stt.TrialID
FULL JOIN [Status] stat ON t.StatusID = stat.ID
FULL JOIN st ON t.StudyTypeID = st.ID
FULL JOIN State state ON l.StateID = state.ID
FULL JOIN [Status] lstat ON l.StatusID = lstat.ID
FULL JOIN ts ON t.ID = ts.TrialID
FULL JOIN tpdm ON t.ID = tpdm.TrialID
WHERE ((t.ID IS NOT NULL)
AND (EligibleHealthyVolunteers IS NULL OR EligibleHealthyVolunteers = 1 OR (0 = 0 AND EligibleHealthyVolunteers = 0))
AND (eligiblegenderid is null OR eligiblegenderid = 1 OR eligiblegenderid = 3)
AND ((EligibleMinAge <= 28 AND EligibleMaxAge >= 28) OR (EligibleMinAge <= 28 AND EligibleMaxAge is null) OR (EligibleMinAge IS NULL AND EligibleMaxAge >= 28))
AND (HYID = 6 AND (hy.Disqualify = 0 OR hy.Disqualify IS NULL AND NOT EXISTS (SELECT * FROM hy WHERE t.id = hy.TrialID AND hy.Req =1)) OR HYID = 6 AND hy.req = 1)
AND (PDT_ID IN (1) AND ( pdt.Disqualify = 0 OR pdt.Disqualify IS NULL AND NOT EXISTS (select * from pdt where t.id = pdt.TrialID AND pdt.Req = 1)) OR PDT_ID IN (1) AND (pdt.Req = 1 AND (pdt.Disqualify = 0 or pdt.Disqualify is null )))
) AND ((3959 * acos(cos(radians(34.18)) * cos(radians(l.Latitude)) * cos(radians(l.Longitude) - radians(-118.46)) + sin(radians(34.18)) * sin(radians(l.Latitude)))) <= 300 OR l.Latitude IS NULL) AND t.IsPublished = 1 AND (t.StatusID = 1 OR t.StatusID = 2)
I've changed/shortened some table names just for security/privacy reasons.
Edit:
I think i am close to getting this working, but I'm getting tripped up on the logic again.
I have the following bit of sql:
AND ( exists (SELECT * FROM pdt WHERE Req = 1 AND trialid = t.id AND pdT_ID IN (2) ) AND EXISTS (SELECT * FROM pdt WHERE Req = 1 AND trialid = t.id ) )
I'm not sure how to structure this. Those two exists statement should make the whole thing true in the following combination:
True & False
True & True
False & False
If it's False & True, then the whole thing is false. In other words if there is a Req =1 AND the PDT_ID that is marked as Req=1 is not in our list (in the example above the list just contains '2') then return false.
EDIT:
I think i finally got it.
AND NOT EXISTS (SELECT * FROM pdt WHERE Disqualify = 1 AND trialid = t.id AND PDT_ID IN (2) )
AND NOT ( NOT exists (SELECT * FROM pdt WHERE Req = 1 AND trialid = t.id AND PDT_ID IN (2) ) AND EXISTS (SELECT * FROM pdt WHERE Req = 1 AND trialid = t.id ) )
So far this seems to work in testing. Although I'm only working with two values of PDT_ID. If this does resolve my problem, i will come back and give someone the credit for helping me.
SELECT *
FROM TABLEB B
WHERE
(
B.REQUIRED = 1
AND EXISTS
(
SELECT 1
FROM TABLEA A
WHERE A.ID =B.TABLEA_ID
)
)
OR
(
B.REQUIRED != 1
AND B.DISQUALIFIES <> 1
)
OR
(
B.REQUIRED != 1
AND B.DISQUALIFIES = 1
AND EXISTS
(
SELECT 1
FROM TABLEA A
WHERE A.ID =B.TABLEA_ID
)
)
UPDATE - after the EDIT and explanation from OP:
Change the line
FULL JOIN pdt on t.ID = pdt.trialid
To
FULL JOIN (SELECT * FROM pdt BB WHERE
BB.TrialID IN (SELECT AA.ID FROM Trial AA WHERE AA.ID = BB.TrialID) AND
1 > (SELECT COUNT(*) FROM Trial A
LEFT OUTER JOIN pdt B ON B.Req != 1 AND B.Disqualify != 1 AND B.TrialID = A.ID
WHERE B.TrialID IS NULL)) pdt ON t.ID = pdt.TiralID
AND change the line before last from
AND (PDT_ID IN (1) AND ( pdt.Disqualify = 0 OR pdt.Disqualify IS NULL AND NOT EXISTS (select * from pdt where t.id = pdt.TrialID AND pdt.Req = 1)) OR PDT_ID IN (1) AND (pdt.Req = 1 AND (pdt.Disqualify = 0 or pdt.Disqualify is null )))
To
AND PDT_ID IN (1)
(You seem to have found a solution, yet I've decided to share my thoughts about this problem anyway.)
Given you've got a set of TableA IDs, each of which is accompanied by a set of some values, and you want to test the entire row set against this TableB thing using the rules you've set forth, I think the entire checking process might look like this:
Match every pair of TableA.ID and Value against TableB and get aggregate maximums of Required and Disqualifies for every TableA.ID along the way.
Derive a separate list of TableA_ID values with their corresponding maximum values of Required, from TableB. That will be for us to know whether a particular TableA_ID must have a required value at all.
Match the row set obtained at Stage 1 against the derived table (Stage 2) and check the aggregate values:
1) if the actual aggregate Disqualifies for a TableA_ID is 1, discard this TableA_ID set;
2) if a TableA_ID has a match in the Stage 2 derived table and the aggregate maximum of Required that we obtained at Stage 1 doesn't match the maximum Required in the derived table, discard the set as well.
Something tells me that it would be better at this point to move on to some sort of illustration. Here's a sample script, with comments explaining which part of the script implements which part of the description above:
;
WITH
/* this is the row set to be tested and which
is supposed to contain TableA.IDs and Values */
testedRowSet AS (
SELECT
TableA.ID AS TableA_ID,
SomethingElse.TestedValue AS Value,
...
FROM TableA
JOIN SomethingElse ON some_condition
...
),
/* at this point, we are getting the aggregate maximums
of TableB.Required and TableB.Disqualifies for every
TableA_ID in testedRowSet */
aggregated AS (
SELECT
testedRowSet.TableA_ID,
testedRowSet.Value,
...
DoesHaveRequiredValues = MAX(CASE TableB.Required WHEN 1 THEN 1 ELSE 0 END) OVER (PARTITION BY testedRowSet.TableA_ID),
HasDisqualifyingValues = MAX(CASE TableB.Disqualifies WHEN 1 THEN 1 ELSE 0 END) OVER (PARTITION BY testedRowSet.TableA_ID)
FROM testedRowSet
LEFT JOIN TableB ON testedRowSet.TableA_ID = TableB.TableA_ID
AND testedRowSet.Value = TableB.Value
),
/* this row set will let us see whether a particular
TableA_ID must have a required value */
properties AS (
SELECT
TableA_ID,
MustHaveRequiredValues = MAX(CASE Required WHEN 1 THEN 1 ELSE 0 END)
FROM TableB
GROUP BY TableA_ID
),
/* this is where we are actually checking the previously
obtained aggregate values of Required and Disqualifies */
tested AS (
SELECT
aggregated.TableA_ID,
aggregated.Value,
...
FROM aggregated
LEFT JOIN properties ON aggregated.TableA_ID = properties.TableA_ID
WHERE aggregated.HasDisqualifyingValues = 0
AND (properties.TableA_ID IS NULL
OR properties.MustHaveRequiredValues = aggregated.DoesHaveRequiredValues)
)
SELECT * FROM tested