I have the following query:
SELECT top 2500 *
FROM table a
LEFT JOIN table b
ON a.employee_id = b.employee_id
WHERE left(a.employee_rc,6) IN
(
SELECT employeeID, access
FROM accesslist
WHERE employeeID = '#client.id#'
)
The sub select in the where clause can return one or several access values, ex:
js1234 BLKHSA
js1234 HDF48R7
js1234 BLN6
In the primary where clause I need to be able to change the integer expression from 6 to 5 or 4 or 7 depending on what the length of the values returned in the sub select. I am at a loss if this is the right way to go about it. I have tried using OR statements but it really slows down the query.
Try using exists instead:
SELECT top 2500 *
FROM table a LEFT JOIN
table b
ON a.employee_id = b.employee_id
WHERE EXISTS (Select 1
FROM accesslist
WHERE employeeID = '#client.id#' and
a.employee_rc like concat(employeeID, '%')
) ;
I don't see how your original query worked. The subquery is returning two columns and that normally isn't allowed in SQL for an in.
Move the subquery to a JOIN:
SELECT TOP 2500 *
FROM table a
LEFT JOIN table b ON a.employee_id = b.employee_id
LEFT JOIN accesslist al ON al.access LIKE concat('%', a.employee_id)
WHERE al.employeeID = '#client.id#'
Like Gordon, I don't quite see how your query worked, so I'm not quite sure if it should be access or employeeID which is matched.
This construct will enable you to do what you said you want to do, have an integer value depend on somethign from a subquery. It's the general idea only, the details are up to you.
select field1, field2
, case when subqueryField1 = 'fred' then 1
when subqueryField1 = 'barney' then 2
else 3 end integerValue
from table1 t1 join (
select idField subqueryField1, etc
from whereever ) t2 on t1.idFeld = t2.idField
where whatever
Also, a couple of things in your query are questionable. First, a top n query without an order by clause doesn't tell the database what records to return. Second, 2500 rows is a lot of data to return to ColdFusion. Are you sure you need it all? Third, selecting * instead of just the fields you need slows down performance. If you think you need every field, think again. Since the employee ids will always match, you don't need both of them.
Related
I want to check that an amount of likes the users received in all their personal pictures is at least twice as large as the number of likes received in the group pictures in which they are tagged.
In case the user is not tagged in any group photo but is tagged in a personal picture that has received at least one like, it will be returned.
My Question is:
How can I make a comparison between 2 sum functions
Where one result of the sum is returned in the nested query and compared with the external query.
Can I set an auxiliary variable to enter the sum value in it and compare it?
Thanks for the helpers:)
Select distinct UIP.userID
From tblUserInPersonalPic UIP
where **sum(UIP.numOfLikes) over (Partition by UIP.userID)*0.5** >
(Select distinct U.userID, sum(P.numOfLikes) over (Partition by U.userID)
From tblgroupPictures P left outer join
tblUserInGroupPic U On P.picNum=U.picNum
group by U.userID,P.numOfLikes,P.picNum)
It's kinda hard to know for sure, and of course I can't test my answer,
but I think you can do it with a couple of left joins, group by and having:
SELECT Personal.UserId
FROM tblUserInPersonalPic Personal
LEFT JOIN tblUserInGroupPic UserInGroup ON Personal.userID = UserInGroup.UesrId
LEFT JOIM tblgroupPictures GroupPictures ON UserInGroup.picNum = GroupPictures.picNum
GROUP BY Personal.userID
HAVING SUM(GroupPictures.numOfLikes) * 2 < SUM(Personal.numOfLikes)
Please note: When posting sql questions it's always best to provide sample data as DDL + DML (Create table + insert into statements) and desired results, so that who ever answers you can test the answer before posting it.
Try using two ctes..pseudo code.Also note distinct in second query will not even work,since you are returning two columns,so i changed it it below,so that you can get that column as well
;with tbl1
as
(
select a,sum(col1) as summ
from
tbl1
)
,tbl2
as
(
select userid,sum(Anothersmcol) as sum2
from tbl2
)
select tbl1.columns,tbl2.columns
from
tbl1 t1
join
tbl2 t2
on t1.sumcol>t2.sumcol
You can't use window functions in a where clause. Define it in a subquery:
select *
from (
select sum(...) over (...) as Sum1
, OtherColumn
from YourTable
) sub
where Sum1 < (...your subquery...)
I need to limit the results of my query so that it only pulls results where the total number of lines on the ID is less than 4, and am unsure how to do this without losing the select statement columns.
select fje.journalID, fjei.ItemID, fjei.acccount, fjei.debit, fjei.credit
from JournalEntry fje
inner join JournalEntryItem fjei on fjei.journalID = fje.journalID
inner join JournalEntryItem fjei2 on fjei.journalID = fjei2.journalID and
fjei.ItemID != fjei2.ItemID
order by fje.journalID
So if journalID 1 has 5 lines, it should be excluded, but if it has 4 lines, I should see it in my query. Just need a push in the right direction. Thanks!
A subquery with an alias has many names, but it's effectively a table. In your case, you would do something like this.
select your fields
from your tables
join (
select id, count(*) records
from wherever
group by id ) derivedTable on someTable.id = derivedTable.id
and records < 4
I have found a few good resources that show I should be able to merge a select query with an update, but I just can't get my head around of the correct formatting.
I have a select statement that is getting info for me, and I want to pretty much use those results to Update an account table that matches the accountID in the select query.
Here is the select statement:
SELECT DISTINCT SUM(b.workers)*tt.mealTax as MealCost,b.townID,b.accountID
FROM buildings AS b
INNER JOIN town_tax AS tt ON tt.townID = b.townID
GROUP BY b.townID,b.accountID
So in short I want the above query to be merged with:
UPDATE accounts AS a
SET a.wealth = a.wealth - MealCost
Where MealCost is the result from the select query. I am sure there is a way to put this into one, I just haven't quite been able to connect the dots to get it to run consistently without separating into two queries.
First, you don't need the distinct when you have a group by.
Second, how do you intend to link the two results? The SELECT query is returning multiple rows per account (one for each town). Presumably, the accounts table has only one row. Let's say that you wanted the average MealCost for the update.
The select query to get this is:
SELECT accountID, avg(MealCost) as avg_Mealcost
FROM (SELECT SUM(b.workers)*tt.mealTax as MealCost, b.townID, b.accountID
FROM buildings AS b INNER JOIN
town_tax AS tt
ON tt.townID = b.townID
GROUP BY b.townID,b.accountID
) a
GROUP BY accountID
Now, to put this into an update, you can use syntax like the following:
UPDATE accounts
set accounts.wealth = accounts.wealth + asum.avg_mealcost
from (SELECT accountID, avg(MealCost) as avg_Mealcost
FROM (SELECT SUM(b.workers)*tt.mealTax as MealCost, b.townID, b.accountID
FROM buildings AS b INNER JOIN
town_tax AS tt
ON tt.townID = b.townID
GROUP BY b.townID,b.accountID
) a
GROUP BY accountID
) asum
where accounts.accountid = asum.accountid
This uses SQL Server syntax, which I believe is the same as for Oracle and most other databases. Mysql puts the "from" clause before the "set" and allows an alias on "update accounts".
I am trying to filter a single table (master) by the values in multiple other tables (filter1, filter2, filter3 ... filterN) using only joins.
I want the following rules to apply:
(A) If one or more rows exist in a filter table, then include only those rows from the master that match the values in the filter table.
(B) If no rows exist in a filter table, then ignore it and return all the rows from the master table.
(C) This solution should work for N filter tables in combination.
(D) Static SQL using JOIN syntax only, no Dynamic SQL.
I'm really trying to get rid of dynamic SQL wherever possible, and this is one of those places I truly think it's possible, but just can't quite figure it out. Note: I have solved this using Dynamic SQL already, and it was fairly easy, but not particularly efficient or elegant.
What I have tried:
Various INNER JOINS between master and filter tables - works for (A) but fails on (B) because the join removes all records from the master (left) side when the filter (right) side has no rows.
LEFT JOINS - Always returns all records from the master (left) side. This fails (A) when some filter tables have records and some do not.
What I really need:
It seems like what I need is to be able to INNER JOIN on each filter table that has 1 or more rows and LEFT JOIN (or not JOIN at all) on each filter table that is empty.
My question: How would I accomplish this without resorting to Dynamic SQL?
In SQL Server 2005+ you could try this:
WITH
filter1 AS (
SELECT DISTINCT
m.ID,
HasMatched = CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END,
AllHasMatched = MAX(CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END) OVER ()
FROM masterdata m
LEFT JOIN filtertable1 f ON join_condition
),
filter2 AS (
SELECT DISTINCT
m.ID,
HasMatched = CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END,
AllHasMatched = MAX(CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END) OVER ()
FROM masterdata m
LEFT JOIN filtertable2 f ON join_condition
),
…
SELECT m.*
FROM masterdata m
INNER JOIN filter1 f1 ON m.ID = f1.ID AND f1.HasMatched = f1.AllHasMatched
INNER JOIN filter2 f2 ON m.ID = f2.ID AND f2.HasMatched = f2.AllHasMatched
…
My understanding is, filter tables without any matches simply must not affect the resulting set. The output should only consist of those masterdata rows that have matched all the filters where matches have taken place.
SELECT *
FROM master_table mt
WHERE (0 = (select count(*) from filter_table_1)
OR mt.id IN (select id from filter_table_1)
AND (0 = (select count(*) from filter_table_2)
OR mt.id IN (select id from filter_table_2)
AND (0 = (select count(*) from filter_table_3)
OR mt.id IN (select id from filter_table_3)
Be warned that this could be inefficient in practice. Unless you have a specific reason to kill your existing, working, solution, I would keep it.
Do inner join to get results for (A) only and do left join to get results for (B) only (you will have to put something like this in the where clause: filterN.column is null) combine results from inner join and left join with UNION.
Left Outer Join - gives you the MISSING entries in master table ....
SELECT * FROM MASTER M
INNER JOIN APPRENTICE A ON A.PK = M.PK
LEFT OUTER JOIN FOREIGN F ON F.FK = M.PK
If FOREIGN has keys that is not a part of MASTER you will have "null columns" where the slots are missing
I think that is what you looking for ...
Mike
First off, it is impossible to have "N number of Joins" or "N number of filters" without resorting to dynamic SQL. The SQL language was not designed for dynamic determination of the entities against which you are querying.
Second, one way to accomplish what you want (but would be built dynamically) would be something along the lines of:
Select ...
From master
Where Exists (
Select 1
From filter_1
Where filter_1 = master.col1
Union All
Select 1
From ( Select 1 )
Where Not Exists (
Select 1
From filter_1
)
Intersect
Select 1
From filter_2
Where filter_2 = master.col2
Union All
Select 1
From ( Select 1 )
Where Not Exists (
Select 1
From filter_2
)
...
Intersect
Select 1
From filter_N
Where filter_N = master.colN
Union All
Select 1
From ( Select 1 )
Where Not Exists (
Select 1
From filter_N
)
)
I have previously posted a - now deleted - answer based on wrong assumptions on you problems.
But I think you could go for a solution where you split your initial search problem into a matter of constructing the set of ids from the master table, and then select the data joining on that set of ids. Here I naturally assume you have a kind of ID on your master table. The filter tables contains the filter values only. This could then be combined into the statement below, where each SELECT in the eligble subset provides a set of master ids, these are unioned to avoid duplicates and that set of ids are joined to the table with data.
SELECT * FROM tblData INNER JOIN
(
SELECT id FROM tblData td
INNER JOIN fa on fa.a = td.a
UNION
SELECT id FROM tblData td
INNER JOIN fb on fb.b = td.b
UNION
SELECT id FROM tblData td
INNER JOIN fc on fc.c = td.c
) eligible ON eligible.id = tblData.id
The test has been made against the tables and values shown below. These are just an appendix.
CREATE TABLE tblData (id int not null primary key identity(1,1), a varchar(40), b datetime, c int)
CREATE TABLE fa (a varchar(40) not null primary key)
CREATE TABLE fb (b datetime not null primary key)
CREATE TABLE fc (c int not null primary key)
Since you have filter tables, I am assuming that these tables are probably dynamically populated from a front-end. This would mean that you have these tables as #temp_table (or even a materialized table, doesn't matter really) in your script before filtering on the master data table.
Personally, I use the below code bit for filtering dynamically without using dynamic SQL.
SELECT *
FROM [masterdata] [m]
INNER JOIN
[filter_table_1] [f1]
ON
[m].[filter_column_1] = ISNULL(NULLIF([f1].[filter_column_1], ''), [m].[filter_column_1])
As you can see, the code NULLs the JOIN condition if the column value is a blank record in the filter table. However, the gist in this is that you will have to actively populate the column value to blank in case you do not have any filter records on which you want to curtail the total set of the master data. Once you have populated the filter table with a blank, the JOIN condition NULLs in those cases and instead joins on itself with the same column from the master data table. This should work for all the cases you mentioned in your question.
I have found this bit of code to be faster in terms of performance.
Hope this helps. Please let me know in the comments.
Is it allowed to reference external field from nested select?
E.g.
SELECT
FROM ext1
LEFT JOIN (SELECT * FROM int2 WHERE int2.id = ext1.some_id ) as x ON 1=1
in this case, this is referencing ext1.some_id in nested select.
I am getting errors in this case that field ext1.some_id is unknow.
Is it possible? Is there some other way?
UPDATE:
Unfortunately, I have to use nested select, since I am going to add more conditions to it, such as LIMIT 0,1
and then I need to use a second join on the same table with LIMIT 1,1 (to join another row)
The ultimate goal is to join 2 rows from the same table as if these were two tables
So I am kind of going to "spread" a few related rows into one long row.
The answer to your initial question is: No, remove your sub-query and put the condition into the ON-clause:
SELECT *
FROM ext1
LEFT JOIN int2 ON ( int2.id = ext1.some_id )
One solution could be to use variables to find the first (or second) row, but this solution would not work efficiently with indexes, so you might end up with performance problems.
SELECT ext1.some_id, int2x.order_col, int2x.something_else
FROM ext1
LEFT JOIN (SELECT `int2`.*, #i:=IF(#id=(#id:=id), #i+1, 0) As rank
FROM `int2`,
( SELECT #i:=0, #id:=-1 ) v
ORDER BY id, order_col ) AS int2x ON ( int2x.id = ext1.some_id
AND int2x.rank = 0 )
;
This assumes that you have a column that you want to order by (order_col) and Left Joins the first row per some_id.
Do you mean this?
SELECT ...
FROM ext1
LEFT JOIN int2 ON int2.id=ext1.some_id
That's what the ON clause is for:
SELECT
FROM ext1
LEFT JOIN int2 AS x ON x.id = ext1.some_id