TEST SERIES ( ALL Keyword)

Question

what will be the output(how many tupples)

Comments

it will return $4$ tupples,

empty table is trivially true for ALL keyword.

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ans is 4 but i tried on this https://www.w3schools.com/sql/trysql.asp?filename=trysql_select_any&ss=-1                 using query 

SELECT * 
FROM OrderDetails
WHERE OrderID = ALL (SELECT ProductID FROM OrderDetails WHERE Quantity = 100);

and result was 0 tuples.

@joshi_nitish please explain.

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@gari,

there you don't know about the content of table(OrderDetails), what if actually there is some ProductId for a Quantity=10, then your inner query will not return empty, and hence there are chances for =ALL to become false.

try for some large like 100000000000000, then you will see that =ALL will return true.

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on the right side i saw the tables(data).(UNDER your database ).. and chose the oder details as 100 .. it was not in table.....

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so sorry .. 100 is there in the table....you are correct the answer is 4. thanks @ joshi_nitish

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ALL ,ANY ,SOME are trivially true for any comparison on an empty table?

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yes it is 4. The >=,=.. ALL test is vacuously true with an empty subquery.

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@gari,

only ALL is trivially true for empty relation, ANY/SUM are not.

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ANY/SOME :p

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bhavnae samjho, sabdo me kya rakha hai :P

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How it is 4 , as value of C should be equal to all the values of subquery , m not getting

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@nitish

=ALL will always return false right if that subquery returns two/more distinct values?

and had this been asked as =ANY then it will return 0 ?

Answer 1

0 tuples will be selected.

Comments

4 tuples are selected.

Becz all clause is true in case empty set

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yes in case of ALL if every tuple is giving false answer then it will return all rows of table ike in above case 

Answer 2

All will be returned