How I can select a set of rows where each row match a different condition?
Example:
Supposing I have a table with a column called name, I want the result ONLY IF the first row name matches 'A', the second row name matches 'B' and the third row name matches 'C'.
Edit:
I want to do this to work without a fixed size, but in a way I can define the sequence like R,X,V,P,T and it matches the sequence, each one in a row, but in the order.
you can, but probably not in a way you would want:
if your table has a numeric id field, that is incremented with each row, you can self join that table 3 times (lets say as "a", "b" and "c") and use the join condition a.id + 1 = b.id and b.id + 1 = c.id and put you filter in a where clause like: a.name = 'A' AND b.name = 'B' AND c.name = 'C'
but don't expect performance ...
Assuming that You know how to provide a row number to your rows (ROW_NUMBER() in SQL Server, for instance), You can create a lookup (match) table and join on it. See below for explanation:
LookupTable:
RowNum Value
1 A
2 B
3 C
Your SourceTable source table (assuming You already added RowNum to it-in case You didn't, just introduce subquery for it (or CTE for SQL Server 2005 or newer):
RowNum Name
-----------
1 A
2 B
3 C
4 D
Now You need to inner join LookupTable with your SourceTable on LookupTable.RowNum = SourceTable.RowNum AND LookupTable.Name = SourceTable.Name. Then do a left join of this result with LookupTable on RowNum only. If there is LookupTable.RowNum IS NULL in final result then You know that there is no complete match on at least one row.
Here is code for joins:
SELECT T.*, LT2.RowNum AS Matched
FROM LookupTable LT2
LEFT JOIN
(
SELECT ST.*
FROM SourceTable ST
INNER JOIN LookupTable LT ON LT.RowNum = ST.RowNum AND LT.Name = ST.Name
) T
ON LT2.RowNum = T.RowNum
Result set of above query will contain rows with Matched IS NULL if row is not matching condition from LookupTable table.
I suppose you could do a sub query for each row, but it wouldn't perform well or scale well at all and would be hard to maintain.
This may be close to what your after... but I need to know where you're getting your values for A, B, C etc...
Select [insert your fields here]
FROM
(Select T1.Name, T1.Age, RowNum as t1RowNum from T T1 order by name) T1O
Full Outer JOIN
(Select T2.Name, T2.Age, RowNum as T2rowNum From T T2 order By name) T2O
ON T1O.T1RowNum+1 = T2O.T2RowNum
Related
I have multiple SELECT queries which is ran against different tables.
The output of all the queries have the same number of rows (every query when ran individually will have the same number of rows). Is there a way I can combine the output of all these queries into a single result? (Keep out from first query and add the output of next query as a column to the output of the next query). I dont want to save these tables into database as I am just doing some validation testing.
Example:
SELECT AAA,BBB,CCC FROM Table1
SELECT Table2.DDD, Table1.AAA
FROM Table2
INNER JOIN Table1
ON Table1.AAA = Table2.AAA
I tried writing combining the query as
SELECT Table1.AAA,Table1.BBB,Table1.CCC,T1.DDD
FROM Table1,
(SELECT Table2.DDD, Table1.AAA
FROM Table2
INNER JOIN Table1
ON Table1.AAA = Table2.AAA)T1
I tried doing the above combined query, but instead of getting 11 rows as output (both queries above had result of 11 rows), I am getting 35 rows as output.
Hope the question made sense!
You'll need to specify a criteria to match each row the first query with which row of the second query.
If, for example, the column AAA is unique in both queries and you want to match rows with the same values you could do:
select a.*, b.*
from (
SELECT AAA,BBB,CCC FROM Table1
) a
full join join (
SELECT Table2.DDD, Table1.AAA
FROM Table2
INNER JOIN Table1
ON Table1.AAA = Table2.AAA
) b on b.aaa = a.aaa
If there aren't any clear matching rules, you can produce an artificial row number on each result set and use it to match rows. For example:
select
a.aaa, a.bbb, a.ccc,
b.ddd, b.aaa
from (
SELECT AAA, BBB, CCC,
row_number() over(order by aaa) as rn
FROM Table1
) a
full join join (
SELECT Table2.DDD, Table1.AAA,
row_number() over(order by table1.aaa, table2.ddd) as rn
FROM Table2
INNER JOIN Table1
ON Table1.AAA = Table2.AAA
) b on b.rn = a.rn
If you have several results and want to have all of them as additional columns you can simply use ",":
create table temp1 as select '1' as c1 from DUAL;
create table temp2 as select '2' as c2 from DUAL;
create table temp3 as select '3' as c3 from DUAL;
select a.c1, b.c2, c.c3 from temp1 a, (select c2 from temp2) b, (select c3 from temp3) c;
An alternative could also be that you want to have all the results as additional rows then you would use UNION ALL between the individual results.
I have 2 tables, A and B.
I need all columns from A + 1 column from B in my select.
Unfortunately, B has multiples rows(all identicals) for 1 row in A
on the join condition.
I tried but I can't isolate one row in A for one row in B with left join for example while keeping my select.
How can I do this query ? Query in ORACLE SQL
Thanks in advance.
This is a good use for outer apply. The structure of the query looks like this:
select a.*, b.col
from a outer apply
(select top 1 b.col
from b
where b.? = a.?
) b;
Normally, you would only use top 1 with order by. In this case, it doesn't seem to make a difference which row you choose.
You can group by on all columns from A, and then use an aggregate (like max or min) to pick any of the identical B values:
select a.*
, b.min_col1
from TableA a
left join
(
select a_id
, min(col1) as min_col1
from TableB
group by
a_id
) b
on b.a_id = a.id
I have 2 Tables, the table1 and table2.
Table1 has columns P_KEY, ID, some_value, some_value2, ....
Table2 has columns P2_KEY, RELATED_DATA, F_KEY, DATA_VALUE.
P_KEY and ID of table1 are unique pairs.
For each P_KEY (and thus each ID) of table1 there are multiple F_KEY entries of table2 with various data of each ID.
The RELATED_DATA rows have specific values (from a defined range elsewhere), which define the kind of Data stored for each ID.
I need to select the DATA_VALUE of ID where RELATED_DATA is 1 and 500. If one of them or both do not exist, I still want to display the row with (examples):
ID, DATA_VALUE (where RELATED_DATA=500), <empty column>
ID, <empty column>, DATA_VALUE (where RELATED_DATA=1)
ID, <empty column>, <empty column>
ID, DATA_VALUE (where RELATED_DATA=500), DATA_VALUE (where RELATED_DATA=1)
I have an SQL like the below, and I need to display row for A.ID, even when B1.RELATED_DATA and/or B2.RELATED_DATA do NOT exist (no row entry at table2), or this is empty string, having the B1.DATA_VALUE and/or B2.DATA_VALUE cell(s) showing as empty cell(s):
select A.ID, B1.DATA_VALUE, B2.DATA_VALUE
from table1 A, table2 B1, table2 B2
where B1.F_KEY = A.P_KEY
and B2.F_KEY = A.P_KEY
and B1.RELATED_DATA = 500
and B2.RELATED_DATA = 1
and A.ID='OneValue';
Purpose is to know the cases at which when B1.RELATED_DATA=500 and/or B2.RELATED_DATA=1 row do not exist or they are empty strings for ID.
Thank you.
What you'd need to do is to pivot the rows in table2 to get the two data_values as columns, rather than rows. Then you can join that back to table1 like so:
select a.id,
b.data_value_500,
b.data_value_1
from table1 a
inner join (select f_key,
max(case when related_data = 500 then data_value end) data_value_500,
max(case when related_data = 1 then data_value end) data_value_1
from table2
group by f_key) b on (a.p_key = b.f_key)
where a.id = 'OneValue';
N.B. I've used an inner join under the assumption that there will always be a row present in table2 for each p_key in table1. If that's not the case, switch to a left outer join instead.
Also, if you're on Oracle 11g or above, it's possible to use the built in PIVOT functionality to do the pivoting of table2:
select a.id,
b.data_value_500,
b.data_value_1
from table1 a
inner join (select f_key,
data_value_1,
data_value_500
from table2
pivot (max(data_value) for related_data in (1 as data_value_1,
500 as data_value_500)))
where a.id = 'OneValue';
I have 3 tables. All of them have a column - id. I want to find if there is any value that is common across the tables. Assuming that the tables are named a.b and c, if id value 3 is present is a and b, there is a problem. The query can/should exit at the first such occurrence. There is no need to probe further. What I have now is something like
( select id from a intersect select id from b )
union
( select id from b intersect select id from c )
union
( select id from a intersect select id from c )
Obviously, this is not very efficient. Database is PostgreSQL, version 9.0
id is not unique in the individual tables. It is OK to have duplicates in the same table. But if a value is present in just 2 of the 3 tables, that also needs to be flagged and there is no need to check for existence in he third table, or check if there are more such values. One value, present in more than one table, and I can stop.
Although id is not unique within any given table, it should be unique across the tables; a union of distinct id should be unique, so:
select id from (
select distinct id from a
union all
select distinct id from b
union all
select distinct id from c) x
group by id
having count(*) > 1
Note the use of union all, which preserves duplicates (plain union removes duplicates).
I would suggest a simple join:
select a.id
from a join
b
on a.id = b.id join
c
on a.id = c.id
limit 1;
If you have a query that uses union or group by (or order by, but that is not relevant here), then you need to process all the data before returning a single row. A join can start returning rows as soon as the first values are found.
An alternative, but similar method is:
select a.id
from a
where exists (select 1 from b where a.id = b.id) and
exists (select 1 from c where a.id = c.id);
If a is the smallest table and id is indexes in b and c, then this could be quite fast.
Try this
select id from
(
select distinct id, 1 as t from a
union all
select distinct id, 2 as t from b
union all
select distinct id, 3 as t from c
) as t
group by id having count(t)=3
It is OK to have duplicates in the same table.
The query can/should exit at the first such occurrence.
SELECT 'OMG!' AS danger_bill_robinson
WHERE EXISTS (SELECT 1
FROM a,b,c -- maybe there is a place for old-style joins ...
WHERE a.id = b.id
OR a.id = c.id
OR c.id = b.id
);
Update: it appears the optimiser does not like carthesian joins with 3 OR conditions. The below query is a bit faster:
SELECT 'WTF!' AS danger_bill_robinson
WHERE exists (select 1 from a JOIN b USING (id))
OR exists (select 1 from a JOIN c USING (id))
OR exists (select 1 from c JOIN b USING (id))
;
I've been asked to find if totals from one table exceed a certain value. However the identifier I need to group these is stored in another table. So I've figured how to isolate what I need and then copy into excel. However I do understand the principle of summing in SQL, as I've made my own queries that look like this:
SELECT * FROM
(SELECT ID, SUM(Table1.Amount) AS Subtotal FROM Table1 WHERE LineNumber = 1 GROUP BY ID) AS a, Table2 AS b
WHERE a.ID = b.ID
AND a.Subtotal > b.Threshold
In this case, the totals I need to sum all have the same LineNumber from the original table (Table1) so it's easy to compare to a value in a different table. What I want to do is be able to is join a subquery back to the original table, then GROUPBY the identifier and sum from the other table, adding a criteria that the original ID from table one must be a duplicate:
SELECT * FROM
((Table1 as t
INNER JOIN
(SELECT ID FROM Table1
GROUP BY ID HAVING COUNT(ID) >1) as b
ON t.ID = b.ID
Joining criteria back to the original table, I need to do this because the table I need to sum doesn't contain ID,
INNER JOIN Table2 as c
ON t.ID2 = c.ID2
WHERE c.LineNumber = 4
This is where I'm stuck. I want to sum all the LineNumber = 4 for each ID. Again, I had to join using ID2 because ID1 isn't in Table2
Perhaps I'm making this too complicated? Any suggestions would be welcome
Thanks!