Slow left join query
,
28 Sep 2012
| 6 comments
Hello,
This is a left join query and it consumes more than 40 minutes.
select
table2.task_sk,
table1.sub_sk,
table1.sub_id,
sum(table2.items) as items,
sum(table2.amount) as amount,
...
from table1 left join table2
on table1.sub_sk = table2.sub_sk and
Teradata Rank Over Query (Getting one row to left join)
,
13 May 2012
| 5 comments
Hi am new to Teradata and am stuck with a problem
There is an ID table which stores an Unique ID given to each person
Not Exists vs Left Join
,
30 Nov 2011
| 4 comments
I have read somewhere that Not exist will almost always perform better than Left join with null check in where clause,Can someone tell me the reason for this ?
eg :
SEL A.*
FROM TABLE A
WHERE NOT EXISTS
(SEL 1
FROM TABLE B
WHERE A.KEY=B.KEY
)
Would perform better than
How do these queries execute?
,
14 Jun 2010
| 1 comment
There are three SQL statements (a, b & c) below, each of which performs a left join. Can anyone please explain how the execution of these statements differs from the other?
a) select c.c_name, a.n_name
from retail.client c left join retail.area a
on c.c_nationkey = a.n_nationkey
and a.n_name is null;