Table 1:
ID (unqiue), Name, Address
Table 2:
RecordId, ID (key of table 1), Child name
In one query, I want to retrieve all rows of Table 1 with one additional column which will be the count of all record in table 2 from ID (that is number of children for each ID in table 1). Can't figure out how to format a query to retrieve this data.
Simply Join and apply count
select T1.*, COUNT(T2.RECORDID)AS T2COUNT from Table1 T1
INNER JOIN TABLE2 T2 ON T1.ID= T2.ID
--LEFT JOIN TABLE2 T2 ON T1.ID= T2.ID --if you need 0 child records (from commets by #Cha)
GROUP BY T1.ID , T1.Name, T1.Address
The correct way of doing this will be with a OUTER JOIN:
SELECT a.ID, a.Name, a.Address, b.cnt
FROM Table1 a
LEFT OUTER JOIN
(SELECT ID, count(*) cnt from Table2 GROUP BY ID) b
ON a.ID = b.ID
The incorrect way will be with a help of a correlated sub-query:
SELECT a.ID, a.Name, a.Address,
(SELECT count(*) FROM Table2 b WHERE b.ID = a.ID) as cnt
FROM Table1 a
Here is a discussion about correlated subqueries vs OUTER JOINs, if you are interested
Group by table1 fields and count total records in table2:
here T1 alias of table1 and T2 alias of table2.
select T1.ID, T1.Name, T1.Address, count(T2.ID) as total_records
from table1 as T1
left outer join table2 as T2 on T2.ID=T1.ID
group by T1.ID, T1.Name, T1.Address
Related
I have about 10 tables that I make one big nested tables by rounds with the following query:
R1 AS(
SELECT ANY_VALUE(Table1).*, ARRAY_AGG(( SELECT AS STRUCT Table2.* EXCEPT(ID))) AS Table2
FROM Table1 LEFT JOIN Table2 USING(ID)
GROUP BY Table1.ID),
R2 AS(
SELECT ANY_VALUE(R1).*, ARRAY_AGG(( SELECT AS STRUCT Table3.* EXCEPT(ID))) AS Table3
FROM R1 LEFT JOIN Table3 USING(ID)
GROUP BY R1.ID),
...
SELECT ANY_VALUE(R9).*, ARRAY_AGG(( SELECT AS STRUCT Table10.* EXCEPT(ID))) AS Table10
FROM R9 LEFT JOIN Table10 USING(ID)
The thing is that for example in my first table I can have two records with the same ID but some other fields will be different and I want to consider them as two distinct records and thus group by all the fields of the table while I join.
Then I want to do the same with all the "sub-table" (the R tables in the query), so I will able to group by all the fields of the nested tables.
How can I do it easily ?
I tried GROUP BY Table1.* but it doesn't work...
Thank you in advance
Try to_json_string:
...
FROM Table1 t1
...
GROUP BY to_json_string(t1)
You seem to want something like this:
select *
from table1 t1 left join
(select t2.*
from table2 t2
where true
qualify row_number() over (partition by t2.id order by t2.id) = 0
) t2
using (id)
This uses qualify instead of group by to fetch one row.
If you don't want all rows from from table1, you can whittle them down as well:
select *
from (select t1.*
from table1 t1
where true
qualify row_number() over (partition by id, col1, col2 order by id) = 1
) t1 left join
(select t2.*
from table2 t2
where true
qualify row_number() over (partition by t2.id order by t2.id) = 0
) t2
using (id)
How to Group By all fields ...?
I tried GROUP BY Table1.* but it doesn't work...
Consider below example
SELECT ANY_VALUE(t1).*,
ARRAY_AGG(( SELECT AS STRUCT t2.* EXCEPT(ID))) AS Table2
FROM Table1 t1 LEFT JOIN Table2 t2 USING(ID)
GROUP BY FORMAT('%t', t1)
I have two table
table1
table1 contains columns (id,item,quantity1) id PK
The other table
table2
table2 contains columns (no,quantity2,id) id FK
I want to compare quantity1 from table1 with sum(quantity2) from table2(find the same result in quantity1 and quantity2
I mean I want to give me result of quantity1 with the same result in quantity2
quantity1 quantity2
20 20
5 5
I try this but it doesn't work(error in syntax)
SELECT table1.id, table1.quantity1,
table1.item, SUM(table2.quantity2) AS Expr1
FROM table1 INNER JOIN
table2 ON table1.id = table2.id
where table1.quantity1 = Expr1
GROUP BY table1.id, table1.quantity1, table1.item
You can go step by step approach for more clarity. You can use CTE and then join.
;WITH CTE_Table2 AS
(
SELECT id,Sum(quantity2) as quantity_sum
FROM Table2
GROUP BY id
)
SELECT t1.id, t1.quantity1, t1.item, t2.quantity_sum
FROM Table1 AS t1
INNER JOIN CTE_Table2 AS t2
ON t2.id = t1.id
AND t2.quantity_sum = t1.quantity1
To compare aggregates use HAVING:
SELECT table1.id
,table1.quantity1
,table1.item
,SUM(table2.quantity2) AS Expr1
FROM table1
INNER JOIN table2 ON table1.id = table2.id
GROUP BY table1.id, table1.quantity1, table1.item
HAVING SUM(table2.quantity2)=table1.quantity1
I have two tables with structure similar to this:
table1
ID |Field1|Field2
table2
ID|Table1_ID|Date|Notice
I need to left join these tables in MS Access SQL based on max date from second table, but also to include 'Notice' field in new table, so result should be like this:
ID|Field1|Field2|Max_Date|Notice
I can join tables based on max date like this:
SELECT t1.ID, t1.Field1, t1.Field2, t2.Max_date
FROM table1 AS t1
LEFT JOIN
[SELECT Table1_ID, MAX(Date) AS Max_date
FROM table2
GROUP BY Table1_ID] AS t2
ON t1.ID = t2.Table1_ID
How can I include 'Notice' field in this query too?
JOIN again:
SELECT t1.ID, t1.Field1, t1.Field2, t2m.Max_date, t2.Notice
FROM (table1 AS t1 LEFT JOIN
(SELECT Table1_ID, MAX(Date) AS Max_date
FROM table2
GROUP BY Table1_ID
) AS t2m
ON t1.ID = t2m.Table1_ID
) LEFT JOIN
table2 as t2
ON t2.Table1_ID = t2m.Table1_ID AND t2.Date = t2m.Max_Date
select t.* from table1 t where t.id NOT IN(
select Id from t2 where usrId in
(select usrId from t3 where sId=value));
I the result i need is like if there are matching id's in t1 and t2 then those id's should be omitted and only the remaining rows should be given to me. I tried converting into join but it is giving me the result i wanted. Below is my join query.
SELECT t.* FROM table1 t JOIN table2 t2 ON t.Id <> t2.Id
JOIN table3 t3 ON t3.Id=t2.Id WHERE t3.sId= :value
This doesn't feth me the correct result. it was returning all the rows, but i want to restrict the result based on the matching id's in table t1 and table t2. Matching id's should be ommited from the result.I will be passing the value for sId.
I believe this to be an accurate refactor of your query using joins. I don't know if we can do away with the subquery, but in any case the logic appears to be the same.
select t1.*
from table1 t1
left join
(
select t2.Id
from table2 t2
inner join table3 t3
on t2.usrId = t3.usrId
where t3.sId = <value>
) t2
on t1.Id = t2.Id
where t2.Id is null
Let's break down and solve problem step by step.
So your query
select t.* from table1 t where t.id NOT IN(
select Id from t2 where usrId in
(select usrId from t3 where sId=value));
on converting the inner query to JOIN will yield
select t.* from table1 t where t.id NOT IN
(SELECT T2.ID FROM T2 JOIN T3 on T2.UsrID =T3.UsrID and T3.sID=value)
which on further converting to JOIN with outer table will be
select t.* from table1 t LEFT JOIN
(SELECT T2.ID FROM T2 JOIN T3 on T2.UsrID =T3.UsrID and T3.sID=value)t4
ON t.id =T4.ID
WHERE t4.ID is NULL
In case you completely want to remove sub-query you can try like this
SELECT t.*
FROM table1 t
LEFT JOIN T2
ON T.ID=T2.ID
LEFT JOIN T3
ON T3.UsrId=T2.UsrID AND T3.sId=value
WHERE T3.UsrID IS NULL
I have some set of records, but now i have to select only those records from this set which have theeir Id in either of the two tables.
Suppose I have table1 which contains
Id Name
----------
1 Name1
2 Name2
Now I need to select only those records from table one
which have either their id in table2 or in table3
I was trying to apply or operator witin inner join like:
select *
from table1
inner join table2 on table2.id = table1.id or
inner join table3 on table3.id = table1.id.
Is it possible? What is the best method to approach this? Actually I am also not able to use
if exist(select 1 from table2 where id=table1.id) then select from table1
Could someone help me to get over this?
Use left join and then check if at least one of the joins has found a relation
select t1.*
from table1 t1
left join table2 t2 on t2.id = t1.id
left join table3 t3 on t3.id = t1.id
where t2.id is not null
or t3.is is not null
I would be inclined to use exists:
select t1.*
from table1 t1
where exists (select 1 from table2 t2 where t2.id = t1.id) or
exists (select 1 from table3 t3 where t3.id = t1.id) ;
The advantage to using exists (or in) over a join involves duplicate rows. If table2 or table3 have multiple rows for a given id, then a version using join will produce multiple rows in the result set.
I think the most efficient way is to use UNION on table2 and table3 and join to it :
SELECT t1.*
FROM table1 t1
INNER JOIN(SELECT id FROM Table2
UNION
SELECT id FROM Table3) s
ON(t.id = s.id)
Alternatively, you can use below SQL as well:
SELECT *
FROM dbo.Table1
WHERE id Table1.IN ( SELECT table2.id
FROM dbo.table2 )
OR Table1.id IN ( SELECT table3.id
FROM Table3 )