Differentiate between Union, Minus and Intersect

Question

Using example differentiate between Union, Minus and Intersect.
Write code as well

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TheDataMonk 3 years 6 Answers 967 views Grand Master 0

Answers ( 6 )

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    INTERSECT gives you the rows that are found in both queries by eliminating rows that are only found in one or the other query. MINUS gives you the rows that are found in the first query and not in the second query by removing from the results all the rows that are found only in the second query.UNION merges the results of two SELECT statements

  2. Raahul
    1
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    Let us explain this using 2 simple sets-
    A = [1,2,3,4,5,6]
    B=[4,5,6,7,8,9]

    Now A union B = [1,2,3,4,5,6,7,8,9] = All the elements (no repetition) in A and B
    A intersect B = [4,5,6] = elements common between A and B
    A minus B = [1,2,3] = elements of A which are not present in B

    Code-
    A = {1,2,3,4,5,6}
    B= {4,5,6,7,8,9}
    print(A-B) = minus, returns {1,2,3}
    print(A | B) = union, returns {1,2,3,4,5,6,7,8,9}
    print(A.intersection(B)) = intersection, returns {4,5,6}

  3. Medha
    0
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    Lets understand union, intersection and minus with the help of an example-
    S1 = {1,2,3}
    S2 = {3,4,5}
    print(S1.union(S2))
    print(S1.intersection(S2))
    print(S1.difference(S2))

    output-
    {1,2,3,4,5}
    {3}
    {1.2}

    Here, union gives all the values in S1 and S2 with the common value occuring only once.
    Intersection gives the common value between two sets
    Minus(or difference) gives us all the values in S1 that are not present in S2. If we have the same values in both the sets, the difference will be a null set.

  4. apmuralidhar
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    Let’s take the example of two tables-one containing a list of states in India that had an average no. of Covid cases that were higher than the national average in 2020 and the other table containing the same for 2021.

    A union between the two sets would be a list of all states that had an average no. of cases above the national average in 2021 or 2020. There would not be any duplicates here

    SELECT state
    FROM 2021_list
    UNION
    SELECT state
    FROM 2020_list

    A Minus between the 2021 set and 2020 set would be the states that had a higher than average no. of cases in 2021, but not in 2020.

    SELECT state
    FROM 2021_list
    MINUS
    SELECT state
    FROM 2020_list

    An intersect between the 2021 set and 2020 set would be the states that had a higher than average no. of cases in 2021 and not in 2020.

    SELECT state
    FROM 2021_list
    EXCEPT SELECT state
    FROM 2020_list

  5. Shivani agarwal
    1
    Reply

    CREATE TABLE FIRST (ID INTEGER)
    INSERT INTO FIRST(ID) VALUES (1) , (2), (3), (4), (5), (6);

    CREATE TABLE SECOND (ID INTEGER)
    INSERT INTO SECOND(ID) VALUES (4) , (5), (6), (7), (8), (9);

    SELECT ID FROM FIRST
    UNION
    SELECT ID FROM SECOND;

    OUTPUT : (1,2,3,4,5,6,7,8)

    SELECT ID FROM FIRST
    INTERSECT
    SELECT ID FROM SECOND;

    OUTPUT : (4,5,6)

    SELECT ID FROM FIRST
    MINUS
    SELECT ID FROM SECOND;

    OUTPUT : (1,2,3)

  6. khushnuma
    0
    Reply

    Set1= {1,2,3,4,5,6}
    Set2= {3,4,5,7,8,9}
    print(Set.union(Set2))
    print(Set1.intersection(Set2))
    print(Set1.difference(Set2))

    output-
    {1,2,3,4,5, 6,7,8,9}
    {3,4,5}
    {1,2,6}

    Union give all value of set1 & set2.
    Intersection gives common value of between both set.
    Minus gives us all the values in Set1 that are not present in Set2.

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