I have a SQL query that looks like this
Select a.*
From table1 a
where a.ColumnName in
(Select MAX(b.ColumnName)
from table2 b
where b.ColumnName2 in
(
Select MAX(c.columnName)
from table3 c
Group by c.ColumnName2
)
Group by b.ColumnName2
)
I am trying to write this in a join statement. I am positive inner join is what I need to get the right information. If someone could translate this to a join statement, I would be really glad.
Thank you.
EDIT 1:
I tried the typical Join statement that a rookie would.
Select a.*
from table1 a
inner join table2 b
on a.columnname = (Select max(b.columnName) from table2)
inner join table3 c
on b.columnName = (select max(c.columnName) from table3)
Obviously, that didn't work because I get 100,000+ results when I should be getting 800. I tried using an alias for table2 and table3 INSIDE the subselect statements and selecting the columnname using THAT alias like this:
Select max(bPart.columnName from table2 bPart)
Select max(cPart.columnName from table3 cPart)
Still the same result.
PERHAPS....
Though I'm not sure why a join is needed. Performance wise exists would likely be fastest, and since you're not returning values from table2 or 3 it seems like it would be the best approach.
SELECT a.*
FROM table1 a
INNER JOIN (SELECT MAX(ColumnName) MColumnName, columnname2
FROM table2
GROUP BY columnName2) B
ON A.columnName = B.mColumnName
INNER JOIN (SELECT MAX(columnName) mColumnName
FROM table3
GROUP BY ColumnName2) C
ON B.columname2 = C.MColumnName
Related
I have a SQL query like this:
SELECT *
FROM table1
INNER JOIN table2 ON table1.key = table2.key
INNER JOIN table3 ON table1.var = table3.var
INNER JOIN table4 ON table1.field = table4.field
but I only want to include the table3 join if a variable has a certain value (iMarket=250 and above)
I'm trying to get this sort of condition working:
SELECT *
FROM table1
INNER JOIN table2 ON table1.key = table2.key
CASE
WHEN iMarket > 250
THEN INNER JOIN table3 ON table1.var = table3.var
END
INNER JOIN table4 on table1.field = table4.field
This is pseudo-code but it approximates to what I'm trying to do. Nothing works. Is there an easier way of doing it? I want to exclude this join because it always fails if that variable is below a certain value. Thank you all!
As easy to include condition in join on clause:
SELECT * from table1
INNER JOIN table2 on table1.key=table2.key
INNER JOIN table3 on iMarket>250 and table1.var=table3.var
INNER JOIN table4 on table1.field=table4.field
Remember than you should use outer joins if you need all values from other tables despite the fact that they are no matches for table3, perhaps you are looking for this behavior:
SELECT * from table1
INNER JOIN table2 on table1.key=table2.key
INNER JOIN table4 on table1.field=table4.field
left outer join --<--
table3 on iMarket>250 and table1.var=table3.var
I have 3 Tables:
TableA(IDRem, IDPed, IDOP)
TableB(IDOP, IDPed)
TableC(IDPed, InvoiceDate)
I need a select to JOIN the records of TableA and TableC, but there are two possible conditions:
IF IDPed on TableA IS NOT NULL, then join directly to TableC by IDPed
ID IDPed on TableA IS NULL, then join to TableB by IDOp, and then join TableB to TableC by IDPed
So far i try this:
SELECT
TableA.*
,(CASE WHEN TableC.InvoiceDate IS NULL
THEN TableC2.InvoiceDate
ELSE TableC.InvoiceDate
END) AS InvoiceDate
FROM
TableA
LEFT JOIN TableC on TableA.IDPed = TableC.IDPed
LEFT JOIN TableB on TableB.IDOp = TableA.IDOp
INNER JOIN TableC as TableC2 on TableC2.IDPed = TableB.IDPed
The problem with this is that every field o tableA I want to include in the select I need to do a case...when to determine if the origin is tableA or TableA2.
Is there a better way of doing this? Thanks!
For complex joins you are better served in TSQL using cross apply:
When should I use Cross Apply over Inner Join?
select IDRem, IDPed, IDOP from TableA a
cross apply(
select IDOP, IDPed from TableB binner
where a.IDop = binner.IDop
) b
cross apply(
select IDPed, InvoiceDate cinner
where b.IDPed = cinner.IDPed
) c
where ...
Strictly psuedo-code but should give you a start.
You could try doing both JOINs and use UNION ALL
Edit: As pointed out in the comment by Vladimir Baranov, there's no need to check if a.IdPed IS NULL on the first SELECT since if it is, the JOIN would return no rows.
SELECT
a.*,
c.InvoiceDate
FROM TableA a
INNER JOIN TableC c ON c.IdPed = a.IdPed
UNION ALL
SELECT
a.*,
c.InvoiceDate
FROM TableA a
INNER JOIN TableB b ON b.IdOp = a.IdOP
INNER JOIN TableC c ON c.IdPed = b.IdPed
WHERE a.IdPed IS NULL
I have three tables
table1 -> xt1, yt1, zt1;
table2 -> xt2
table3 -> yt3, zt3
SELECT xt1, yt1, zt1
From table1, table3
Where xt1
NOT IN
(SELECT DISTINCT table1.xt1 FROM table2 INNER JOIN table1 ON
table1.xt1 = Replace(table2.xt2,',',''))
And table1.yt1 = table3.yt3
AND table1.zt1 = table3.zt3
it is working correctly but i take long time.
if i replace NOT IN with Not exists it return empty set.
SELECT xt1, yt1, zt1
From table1, table3
Where Not exists
(SELECT DISTINCT table1.xt1 FROM table2 INNER JOIN table1 ON
table1.xt1 = Replace(table2.xt2,',',''))
And table1.yt1 = table3.yt3
AND table1.zt1 = table3.zt3
the results of the second select should be 6 rows but it returns notiong with not exists.
also if i tried to change the compare part to
table1.xt1 != Replace(table2.xt2,',','') and remove the NOT IN
select it get outof memory error.
So is this the best way to write my query and why it return empty set with Not exists
thank you.
Ok, first of all, I changed your implicit join to an explicit one. Then I fixed the NOT EXISTS so it correlates to the outer table1:
SELECT t1.xt1, t1.yt1, t1.zt1
FROM table1 AS t1
INNER JOIN table3 AS t3
ON t1.yt1 = t3.yt3
AND t1.zt1 = t3.zt3
WHERE NOT EXISTS ( SELECT 1
FROM table2 AS t2
INNER JOIN table1 AS t1_1
ON t1_1.xt1 = REPLACE(t2.xt2,',','')
AND t1_1.xt1 = t1.xt1) ;
which can be simplified further to:
SELECT t1.xt1, t1.yt1, t1.zt1
FROM table1 AS t1
INNER JOIN table3 AS t3
ON t1.yt1 = t3.yt3
AND t1.zt1 = t3.zt3
WHERE NOT EXISTS ( SELECT 1
FROM table2 AS t2
WHERE t1.xt1 = REPLACE(t2.xt2,',','')
) ;
You need to select IN or exist depending upon the size of inner query. when there is a outer query and inner-sub-query, if the result of sub query is small, In is preferred as outer query is selected based upon result of sub-query.
if the result of sub-query is large, exist is preferred as outer query is evaluated first.
I have two query which has successfully inner join
select t1.countResult, t2.sumResult from (
select
count(column) as countResult
from tableA join tableB
on tableA.id = tableB.id
group by name
)t1 inner join (
select
sum(column) as sumResult
from tableA
join tableB
on tableA.id = tableB.id
group by name
)t2
on t1.name= t2.name
The above query will return me the name and the corresponding number of count and the sum. I need to do a comparison between the count and sum. If the count doesnt match the sum, it will return 0, else 1. And so my idea was implementing another outer layer to wrap them up and use CASE WHEN. However, I've failed to apply an outer layer just to wrap them up? This is what I've tried:
select * from(
select t1.countResult, t2.sumResult from (
select
count(column) as countResult
from tableA join tableB
on tableA.id = tableB.id
group by name
)t1 inner join (
select
sum(column) as sumResult
from tableA
join tableB
on tableA.id = tableB.id
group by name
)t2
on t1.name= t2.name
)
Alright the problem can be solved by simply assigning a name to the outer layer.
select * from(
select t1.countResult, t2.sumResult from (
select
count(column) as countResult
from tableA join tableB
on tableA.id = tableB.id
group by name
)t1 inner join (
select
sum(column) as sumResult
from tableA
join tableB
on tableA.id = tableB.id
group by name
)t2
on t1.name= t2.name
) as whatever //SQL Server need a name to wrap
Hope it will help any newbie like me
Ok, so far you have selected everything your first select has generated (kinda useless, but a start for what you want ;) )
SELECT CASE
WHEN countresult=sumresult THEN 'Equal'
ELSE 'Not'
END
FROM ( --your join select --
)
I don't have any sample data to test this so can just go on your code.
Your queries for t1 & t2 look identical - why don't you just do a sum & count in 1 step?
SELECT COUNT(column) AS countResult
,SUM(column) AS sumResult
FROM tableA INNER JOIN tableB
ON tableA.id = tableB.id
GROUP BY name
Also, as you mention you are a newb - read up on Common Table Expressions in SQL Server.
Before SQL 2005 you had to write these convoluted queries within queries within...
Get into the habit of using CTEs now.
i have two Identical tables in my SQL database these tables consist of Item Code and QTY each.
I need to see which items in both tables that have different quantities AND the items that
don't exist in the other table
I tried using FULL OUTER JOIN ON ITEMCODE=ITEMCODE AND QTY<>QTY
IT IS NOT WORKING
the result i am getting is something like that:
http://www.sendspace.com/file/nmb7yu
Try something like this:
SELECT c.Code ,
t1.Code ,
t1.Qty ,
t2.Code ,
t2.Qty
FROM ( SELECT Code
FROM dbo.Table1
UNION
SELECT Code
FROM dbo.Table2
) c
LEFT OUTER JOIN dbo.Table1 t1 ON c.Code = t1.Code
LEFT OUTER JOIN dbo.Table2 t2 ON c.Code = t2.Code
WHERE t1.Code IS NULL
OR t2.Code IS NULL
OR t1.Qty <> t2.Qty
Since you have a test for inequality in the WHERE clause you're implicitly only including items that are in both tables. This way you include items that are in one table, but not the other, or have the difference in quantity.
select *
from table1 a full outer join table2 b
on a.code = b.code
where a.qty <> b.qty or a.code is null or b.code is null
my lucky guess is that you filtered out rows where code column is null