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What is the use of exists function in qlikview
check this
The exists() function checks if a value of the field (first parameter of the exist function) has been loaded anywhere in the script. This parameter is always a field, never an expression. The exists in the second load compares existing F3 values against incoming F1 values here:
WHERE NOT Exists(F3, F1);
You suggestion about combination F1 and F2 is not going to work the same way because it is logicallydifferent. And, you still must use field as the first parameter, can't avoid F3 here:
TABLE1:
LOAD *, F1&F2 as F3 INLINE [
F1, F2
1, a
2, b
3, c
];
concatenate
LOAD * INLINE [
F1, F2
4, d
4, e
]
WHERE NOT Exists(F3, F1&F2);
The logical difference is easy to see if change data a little, add another line into the 1st table:
4, z
The example with (F1 as F3) is going to eliminate both record from the table 2, because there is F3=4 in table 1
The combination logic will keep all the data because all combinations are unique in this case.
See this small example for explaination
Load table like this
TableA:
LOAD * Inline
[
C1
A
B
C
];
TableB:
LOAD * Inline
[
C2
A
B
E
F
] Where not Exists(C1,C2);
thankyou Mvrchowdary Rao
Looks like you are asking interview or test question on community? Please read these concepts instead of getting instant answers.
I'd strongly recommend reading following posts:
QlikCommunity Tip: How to get answers to your post?
Its not about the answer, rather it’s about the question…
Good luck!
Cheers,
DV
www.QlikShare.com
Another copied question! All these questions are Interview Questions. I've listed loads of interview questions on my blog without answers and Chandramohan just copied them from my blog. I wish he could have changed the text format but well he didn't!!
Copied from this URL:
http://qlikshare.com/qlikview-interview-qa/
Cheers,
DV