I’m using oracle. I have two table A and B
Table A has 8000 rows and 5 five columns
Table B has 5500 rows and same 5 columns
All of 5500 rows in table B are contained in Table A and they are the same
I have a query like
With t1 as (select distinct(id) from table A/B)
,T2 as (select a.id, c.value, d.value from Table A/B a
Join table c c on “conditions”
Join table d d on “conditions”
) select * from t2
So the query with Table A works excellent but with Table B it freezes for eternity.
Data types and other properties are equal in table A and table A.
Where should i look for the problem?
I tried to explain plan but differences only in row “PX PARTITION HASH JOIN-FILTER” in Table A and “PX BLOCK ITERATOR ADAPTIVE” in table B
Related
I have created two tables as below in hive
create table test1(id string);
create table test2(id string);
test1 has values as given below
1
1
test2 has values as given below
1
1
When I am joining these two tables I am getting output with
1
1
1
1
This is the query used :
select a.id from test1 a,test2 b where a.id=b.id;
Please help I expected the output to be as
1
1
I am using cloudera distribution
Better use ANSI join syntax:
select a.id
from test1 a
inner join test2 b on a.id=b.id
The expected output cannot be the result of your join because for each a.id all matching rows from a and b are selected. For the first row from a it will be two matching rows in b. For the second row from a it will be also two matching rows from b. So it will be four rows totally.
You can apply distinct to the second table before join for example.
select a.id
from test1 a
inner join (select distinct b.id from test2 b) b on a.id=b.id
In this case for each row in table a it will be single matching row in table b.
See this lesson to understand JOINS better: https://www.coursera.org/learn/analytics-mysql/lecture/kydcf/joins-with-many-to-many-relationships-and-duplicates
I am trying a left join in Hive Query, but it does not seem to work. It returns me columns only from left table:
create table mb.spt_new_var as select distinct customer_id ,target from mb.spt_201603 A
left outer join mb.temp B
on (A.customer_id=B.cust_id);
I tried selecting few records from table B based on the some random customer_id from table A and it returns some records. But if I try the left join on table A, it returns me only columns from table A. The data-type of both the IDs is same(int). what could be the possible reason behind this?
Sample Table A:
Customer_account_id target
12356 1
34245 0
12356 1
.... ..
Sample Table B:
Cust_id col1 col2 col3
12356 ..
12567 ..
24426 ..
...
Table A has some 1m records, while table B has some 30m records. There is possibility of some duplicate IDs in table A and Table B.
I'm a bit confused. Hive is returning the columns that you specify in the query:
select distinct a.customer_id, a.target
from mb.spt_201603 a left outer join
mb.temp b
on a.customer_id = b.cust_id;
If you want columns from the second table, you need to select them:
select distinct a.customer_id, a.target, b.col1, b.col2
from mb.spt_201603 a left outer join
mb.temp b
on a.customer_id = b.cust_id;
I am trying to subtract sequences MN_SEQ from Table C generated based on join with other tables.
Here is the problem.
Query 1 -
Select M_Seq from Table C, Table A, Table B where C.date_sk=A.MTH_END_DT
and B.Loan_seq=A.Loan_seq
Query 2 -
Select M_Seq from Table C, Table B where C.date_sk=B.ORIG_DT
I have to get difference between 2 M_SEQ generated from the result set of query 1 and Query 2.
Below is what i tried, but I am getting error.
select mn_seq -mn_seq from
((select mn_seq from Table C, Table A, Table B where B.MTH_END_DT=C.DATE_SK and B.LOAN_SEQ=A.LOAN_SEQ)a,
(select mn_seq from Table C , Table B where B.ORIG_DT=C.DATE_SK
)b)
T
Kindly provide inputs . I am not sure if this is the right way to do it. I tried just using "-" between queries but didnt work. Thanks!
Try this..
SELECT (SELECT mn_seq
FROM TABLE c, TABLE a, TABLE b
WHERE b.mth_end_dt = c.date_sk
AND b.loan_seq = a.loan_seq) -
(SELECT mn_seq FROM TABLE c, TABLE b WHERE b.orig_dt = c.date_sk)
FROM dual
I assume both the mn_seq are NUMBER and also your WHERE clause returns only one record in each of the inner queries.
Here is what I needed:
I have:
Table A PT*,NAME,AGE
Table B PT*,COURSE,RESULT
Table C PT*,COURSE,RESULT,RANk
Wondering how could I UNION Table B and Table C and later Merge with Table A to get the output as below(Table D). PT is the PKey among all.
PT NAME AGE COURSE RESULT RANK
100 SLK 29 Test1 29 - result of merge between Table A and Table B
200 AAR 30 Test2 23 10 - result of merge between Table A and Table C
To get desirable output just perform a simple SQL SELECT query:
SELECT A.PT, A.NAME, A.AGE, B.COURSE, B.RESULT, C.RANK
FROM
A join B on A.PT=B.PT
join C ON A.PT = C.PT
Why you need COURSE, RESULT fields in table C, by the way, as they are already stored in table B?
i have 3 tables
table A, table B and a relational table C
table A has ta_id as primary key along with other columns
table B has tb_id as primary key along with other columns
table C has ta_id, tb_id as foreign keys along with other columns.
i wanted to find all the rows of table B which have a common ta_id in table C.
my sql query for the that is.
SELECT B.ta_id,
B.type,
B.language,
B.user_id
FROM B
INNER JOIN C
ON B.tb_id=C.tb_id
where C.ta_id = 1
ORDER BY B.user_id
the above query seems to be working..
but now i have another table called table D with D.tb_id as a foreign key (which is primary key in table B ).
each row of table B has 0 or more rows associated in table D or we can say
1 or more rows in table D has exactly one corresponding row in table B.
Now i want to list my each row of table B with all the associated rows of table D.
so it should look like this.
first row of table B
first corresponding row of table D
second corresponding row of table D
...
..
second row of table B
first corresponding row of table D
second corresponding row of table D
...
..
so in a way i am mixing the contents of 2 tables in display
Please tell me how to achieve this using a sql query..?
Waiting for reply..!
Thanks
Big O
Just add another inner join like this:
SELECT B.ta_id, B.type, B.language, B.user_id
FROM B
INNER JOIN C
ON B.tb_id=C.tb_id
INNER Join D
ON B.tb_id=D.tb_id
WHERE C.ta_id = 1
ORDER BY B.user_id
I believe that you can use SQL views easily to query data with lot of tables
You cannot do this in one simpl query, you need a loop. Think about what you are trying to do...
TABLE B ROW 1
TABLE D ROW 1 (Matching Row 1 Table B)
TABLE D ROW 2 (Matching Row 1 Table B)
TABLE D ROW 3 (Matching Row 1 Table B)
TABLE B ROW 2
TABLE D ROW 1 (Matching Row 2 Table B)
TABLE D ROW 2 (Matching Row 2 Table B)
TABLE D ROW 3 (Matching Row 2 Table B)
ETC...
ETC...
The only way you can do this is inside a stored procedure using temp tables and looping.