I'm trying to select all records from a table "Table1" but I want a new column called "HasException" that contains a "0" or a "1". "HasException" must be "0" if the count of row matching the current Id from "Table2" is equal to 0, else it returns 1.
Here's what I've done so far, but it doesn't works:
SELECT *,
CONVERT(bit, (CASE WHEN (SELECT count(Id) FROM Table2 WHERE Table1.Id=Table2.Id) = 0 THEN 0 ELSE 1 END)) AS HasException
FROM Table1
You want to join the tables (and group on ID) before you can compare the two values like this:
SELECT dbo.Table_1.*,
CASE WHEN COUNT(dbo.Table_2.ID) = 0 THEN
0
ELSE
1
END
AS HasException
FROM dbo.Table_1 LEFT OUTER JOIN
dbo.Table_2 ON dbo.Table_1.ID = dbo.Table_2.ID
GROUP BY dbo.Table_1.ID
perhaps something like, assuming you meant table2?
SELECT *,
CAST(CASE WHEN COUNT(table2.id) = 0 THEN 0 ELSE 1 END AS bit) AS HasException
FROM
Table1
LEFT JOIN
Table2 ON Table1.Id=Table2.Id
GROUP BY
Table1.id
select
T1.*,
case when T2.Id is null then 0 else 1 end as HasException
from Table1 as T1
left outer join
(
select distinct Id
from Table2
) as T2
on T1.Id = T2.Id
Related
Lets assume we have the following table1:
1 2 3
a x m
a y m
b z m
I want to do an inner join on the table
INNER JOIN tabel2 ON table1.2 = table2.2
Somehow like this, but additional a condition that the value of table1.1 not unique. Thus on table1.1 = b no inner join will occure in this example.
What is the best way to achieve this?
Using a an aggregate in a sub query is how I would do it
SELECT *
FROM table1
JOIN table2
ON table1."2" = table2."2"
JOIN (
SELECT "1"
FROM table1
GROUP BY "1"
HAVING COUNT(*) > 1
) AS sub_q
ON sub_q."1" = table1."1";
Another option might be a cte or temporary table to hold the rows you're joining on
WITH _cte AS
(
SELECT "1"
FROM table1
GROUP BY "1"
HAVING COUNT(*) > 1
)
SELECT *
FROM table1
JOIN table2
ON table1."2" = table2."2"
JOIN _cte AS cte
ON cte."1" = table1."1";
temp table:
CREATE TEMPORARY TABLE _tab
(
"1" varchar
);
INSERT INTO _tab
SELECT "1"
FROM table1
GROUP BY "1"
HAVING COUNT(*) > 1;
SELECT *
FROM table1
JOIN table2
ON table1."2" = table2."2"
JOIN _tab AS tab
ON tab."1" = table1."1";
Name Value AnotherColumn
-----------
Pump 1 8000.0 Something1
Pump 1 10000.0 Something2
Pump 1 10000.0 Something3
Pump 2 3043 Something4
Pump 2 4594 Something5
Pump 2 6165 Something6
My table looks something like this. I would like to know how to select max value for each pump.
select a.name, value from out_pumptable as a,
(select name, max(value) as value from out_pumptable where group by posnumber)g where and g.value = value
this code does the job, but i get two entries of Pump 1 since it has two entries with same value.
select name, max(value)
from out_pumptable
group by name
select name, value
from( select name, value, ROW_NUMBER() OVER(PARTITION BY name ORDER BY value desc) as rn
from out_pumptable ) as a
where rn = 1
SELECT
b.name,
MAX(b.value) as MaxValue,
MAX(b.Anothercolumn) as AnotherColumn
FROM out_pumptabl
INNER JOIN (SELECT
name,
MAX(value) as MaxValue
FROM out_pumptabl
GROUP BY Name) a ON
a.name = b.name AND a.maxValue = b.value
GROUP BY b.Name
Note this would be far easier if you had a primary key. Here is an Example
SELECT * FROM out_pumptabl c
WHERE PK in
(SELECT
MAX(PK) as MaxPK
FROM out_pumptabl b
INNER JOIN (SELECT
name,
MAX(value) as MaxValue
FROM out_pumptabl
GROUP BY Name) a ON
a.name = b.name AND a.maxValue = b.value)
select Name, Value, AnotherColumn
from out_pumptable
where Value =
(
select Max(Value)
from out_pumptable as f where f.Name=out_pumptable.Name
)
group by Name, Value, AnotherColumn
Try like this, It works.
select * from (select * from table order by value desc limit 999999999) v group by v.name
Using analytic function is the easy way to find max value of every group.
Documentation : https://learn.microsoft.com/en-us/sql/t-sql/functions/row-number-transact-sql?view=sql-server-ver15
Select name,
value,
AnotherColumn
From(
SELECT Row_Number() over(partition by name order by value desc)as
row_number, *
FROM students
)
Where row_number = 1
SELECT t1.name, t1.Value, t1.AnotherColumn
FROM mytable t1
JOIN (SELECT name AS nameMax, MAX(Value) as valueMax
FROM mytable
GROUP BY name) AS t2
ON t2.nameMax = t1.name AND t2.valueMax = t1.Value
WHERE 1 OR <anything you would like>
GROUP BY t1.name;
SELECT DISTINCT (t1.ProdId), t1.Quantity FROM Dummy t1 INNER JOIN
(SELECT ProdId, MAX(Quantity) as MaxQuantity FROM Dummy GROUP BY ProdId) t2
ON t1.ProdId = t2.ProdId
AND t1.Quantity = t2.MaxQuantity
ORDER BY t1.ProdId
this will give you the idea.
I have two tables shown below. I want to create a new variable (VALUE) based on the logic below and show results in a 3rd table? How can I do this in T SQL?
TABLE_1
ID, DATE
TABLE_2
ID, DATE1, DATE2
Logic to set VALUE:
FOR ALL TABLE_1.ID
IF TABLE_1.DATE IS BETWEEN TABLE_2.DATE1 AND TABLE_2.DATE2
THEN VALUE = 1
ELSE VALUE = 0
IF TABLE_1.ID NOT IN TABLE_2
THEN VALUE = NULL
If you want to see the results for all rows where table_1.id = table_2.id (and table_1 rows that do not have a match on id), then we can use a left join and a case expression:
select
t.id
, t.date
, IsBetween = case
when t.date between t2.Date1 and t2.Date2
then 1
when t2.id is null
then null
else 0
end
, t2.*
from table_1 as t
left join table_2 as t2
on t.id = t2.id
If you only want one row for each row in table_1, and want to know if table_1.data is between any corresponding row in table_2 or not, then we can use a outer apply to select top 1 and a case expression:
select
t.id
, t.date
, IsBetween = case
when t.date between x.Date1 and x.Date2
then 1
when x.id is null
then null
else 0
end
from table_1 t
outer apply (
select top 1 t2.*
from table_2 t2
order by case
when t.date between t2.Date1 and t2.Date2
then 0
else 1
end
) as x
Below sample query is a part of my main query. I found SORT operator in below query is consuming 30% of the cost.
To avoid SORT, there is need of creation of Indexes. Is there any other way to optimize this code.
SELECT TOP 1 CONVERT( DATE, T_Date) AS T_Date
FROM TableA
WHERE ID = r.ID
AND Status = 3
AND TableA_ID >ISNULL((
SELECT TOP 1 TableA_ID
FROM TableA
WHERE ID = r.ID
AND Status <> 3
ORDER BY T_Date DESC
), 0)
ORDER BY T_Date ASC
Looks like you can use not exists rather than the sorts. I think you'll probably get a better performance boost by use a CTE or derived table instead of the a scalar subquery.
select *
from r ... left outer join
(
select ID, min(t_date) as min_date from TableA t1
where status = 3 and not exists (
select 1 from TableA t2
where t2.ID = t1.ID
and t2.status <> 3 and t2.t_date > t1.t_date
)
group by ID
) as md on md.ID = r.ID ...
or
select *
from r ... left outer join
(
select t1.ID, min(t1.t_date) as min_date
from TableA t1 left outer join TableA t2
on t2.ID = t1.ID and t2.status <> 3
where t1.status = 3 and t1.t_date < t2.t_date
group by t1.ID
having count(t2.ID) = 0
) as md on md.ID = r.ID ...
It also appears that you're relying on an identity column but it's not clear what those values mean. I'm basically ignoring it and using the date column instead.
Try this:
SELECT TOP 1 CONVERT( DATE, T_Date) AS T_Date
FROM TableA a1
LEFT JOIN (
SELECT ID, MAX(TableA_ID) AS MaxAID
FROM TableA
WHERE Status <> 3
GROUP BY ID
) a2 ON a2.ID = a1.ID AND a1.TableA_ID > coalesce(a2.MAXAID,0)
WHERE a1.ID = r.ID AND a1.Status = 3
ORDER BY T_Date ASC
The use of TOP 1 in combination with the unexplained r alias concern me. There's almost certainly a MUCH better way to get this data into your results that doesn't involve doing this in a sub query (unless this is for an APPLY operation).
I am trying to use a correlated subquery, but I am trying to limit it to the "best" record. When I use SQL very similiar to what follows, I get two rows per BigTable.identifier, and I wish to have only one. In the 'UNION' statement, the second half is more desirable than the first half. However, sometimes the first half will be needed. Any ideas? Here's the code:
select
BigTable.identifier,
Correlated.ID,
Correlated.Effective_Date,
Correlated.Period_Number
from
BigTable
inner join
(
select
TOP 2147483647
Table3.identifier,
Table4.Effective_Date,
Table4.Period_Number
from
Table3
inner join Table4 on Table3.matching_key = Table4.matching_key
where
Table4.Period_Number = 0
order by Table4.Effective_Date desc
UNION
select
TOP 2147483647
Table3.Identifer,
Table4.Effective_Date,
Table4.Period_Number
from
Table3
inner join Table5 on Table3.matching-key = Table5.matching-key
inner join Table4 on Table5.key1 = Table4.key1 and
Table5.key2 = Table4.key2
where
Table4.period_number = 1
order by Table4.Effective_Date desc
) as Correlated
on BigTable.identifier = Correlated.identifier
If each sub-query in that UNION had some condition which EXCLUDED the row if it was less-preferred, you would never see the less-preferred rows in the UNION.
So, if each were to have a NOT EXISTS (.... a better row in the other side of the union ....), you would eliminate less-preferred rows at the root.
I'm not clear on how you want to use effective date. Assuming you mean that you prefer Period=1 but if the Effective date is less you prefer Period=0, then something like this might work.
select
BigTable.identifier,
Correlated.ID,
Correlated.Effective_Date,
Correlated.Period_Number
from
BigTable
inner join
(
select
TOP 2147483647
Table3.identifier,
Table4.Effective_Date,
Table4.Period_Number
from
Table3
inner join Table4 on Table3.matching_key = Table4.matching_key
where
Table4.Period_Number = 0
AND NOT EXISTS
(select 1
from Table5 T5 inner join Table4 T4
on T5.key1 = T4.key1 and T5.key2 = T4.key2
where Table3.matching-key = T5.matching-key
and (T4.Effective_Date >= Table4.Effective_Date and T4.Period_Number = 1)
)
order by Table4.Effective_Date desc
UNION
select
TOP 2147483647
Table3.Identifer,
Table4.Effective_Date,
Table4.Period_Number
from
Table3
inner join Table5 on Table3.matching-key = Table5.matching-key
inner join Table4 on Table5.key1 = Table4.key1 and
Table5.key2 = Table4.key2
where
Table4.period_number = 1
AND NOT EXISTS
(select 1
from Table4 T4
where Table3.matching-key = T4.matching-key
and (T4.Period_Number > 0)
and (T4.Effective_Date > Table4.Effective_Date and T4.Period_Number = 0)
)
order by Table4.Effective_Date desc
) as Correlated
on BigTable.identifier = Correlated.identifier