We have two tables with the following scheme, where AX and BC are the keys and t

Question

We have two tables with the following scheme, where AX and BC are the keys and the AC input is key in BC:
A (X: Integer, Y: Integer, c: string)
B (C string, Z: real)
What does the following SQL command:
SELECT B. *
FROM B
C WHERE NOT IN (SELECT C
FROM A)

a)SQL command returns all entries in A that are not matched in B
b)SQL command that returns all records in B that are not matched in A
c)SQL command returns all entries that are identical in B and A records but not duplicated
d)SQL command returns all entries in column B and C of Table A


We have two tables with the following scheme, where AX and BC are the keys and the AC input is key in BC:
A (X: Integer, Y: Integer, c: string)
B (C string, Z: real)
SQL command to find the highest Y value in A is




a)SELECT MAX(DISTINCT Y)
FROM A

b)SELECT MAX(Y)
FROM A

c)SELECT Y
FROM A
WHERE Y=MAX(Y)

d)SELECT DISTINCT MAX(Y)
FROM A


The three values logic returns TRUE OR (FALSE OR NOT (Unknown)) valu



a)FALSE
b)UNKNOWN
c)TRUE
d)NULL

Explanation / Answer

Dear,
1)
a)SQL command returns all entries in A that are not matched in B
b)SQL command that returns all records in B that are not matched in A
c)SQL command returns all entries that are identical in B and A records but not duplicated
d)SQL command returns all entries in column B and C of Table A

2)
a)SELECT MAX(DISTINCT Y) FROM A   returns maximum value y from A  (TRUE)

b) SELECT MAX(Y) FROM A   - returns TRUE

c) SELECT Y FROM A WHERE Y=MAX(Y) it results in error

d)SELECT DISTINCT MAX(Y) FROM A TRUE

Hope this will help you

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