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Recent questions tagged joins

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1
ISRO 2024
In SQL the statement $\text{select * from R, S}$ is equivalent to $\text{select * from R natural join S}$ $\text{select * from R cross join S}$ $\text{select * from R outer join S}$ $\text{select * from R inner join S}$
In SQL the statement $\text{select * from R, S}$ is equivalent to$\text{select * from R natural join S}$$\text{select * from R cross join S}$$\text{select * from R outer ...
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3
Self Doubt
I want to join the two tables of movies and actors and then output only those results that have gender =”F”, can you tell me where I am going wrong?
I want to join the two tables of movies and actors and then output only those results that have gender =”F”, can you tell me where I am going wrong?
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4
NIELIT 2017 July Scientist B (IT) - Section B: 55
A table joined with itself is called Join Self Join Outer Join Equi Join
A table joined with itself is calledJoinSelf JoinOuter JoinEqui Join
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5
NIELIT 2017 July Scientist B (IT) - Section B: 56
Consider the join of a relation $R$ with relation $S$. If $R$ has $m$ tuples and $S$ has $n$ tuples, then the maximum size of join is $mn$ $m+n$ $(m+n)/2$ $2(m+n)$
Consider the join of a relation $R$ with relation $S$. If $R$ has $m$ tuples and $S$ has $n$ tuples, then the maximum size of join is$mn$$m+n$$(m+n)/2$$2(m+n)$
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6
Raghuramkrishnan Exercise-4.3 question 11 page no-127 Relational Algebra
Suppliers(sid, sname, address) Parts(pid, pname, color) Catalog(sid, pid, cost) Find the pids of the most expensive parts supplied by suppliers named Yosemite Sham
Suppliers(sid, sname, address)Parts(pid, pname, color)Catalog(sid, pid, cost)Find the pids of the most expensive parts supplied by suppliers named Yosemite Sham
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7
Raghuramkrishnan Exercise-4.3 page-127
Given relation catalog(sid, pid, cost) Find pairs of sids such that the supplier with the first sid charges more for some part than the supplier with the second sid what is the relational algebra expression for this?
Given relationcatalog(sid, pid, cost)Find pairs of sids such that the supplier with the first sid charges more for some part than the supplier with the second sidwhat is ...
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12
JOIN Doubt
in case of outer join for combining two tables, if there is no common attribute does it returns cartesian product just like natural join does?
in case of outer join for combining two tables, if there is no common attribute does it returns cartesian product just like natural join does?
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13
General Doubt: Databases - Joins
A system where commutativity is considered different, in how many ways the join of n relations r1,r2, . . . ,rn can be taken?
A system where commutativity is considered different, in how many ways the join of n relations r1,r2, . . . ,rn canbe taken?
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14
Relational Algebra
Online Site For practicing Relational Algebra https://dbis-uibk.github.io/relax/calc.htm
Online Site For practicing Relational Algebrahttps://dbis-uibk.github.io/relax/calc.htm
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15
UGC NET CSE | July 2018 | Part 2 | Question: 61
In RDBMS, which type of Join returns all rows that satisfy the join condition? Inner Join Outer Join Semi Join Anti Join
In RDBMS, which type of Join returns all rows that satisfy the join condition?Inner JoinOuter JoinSemi JoinAnti Join
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16
MadeEasy Test Series: Databases - Natural Join
Consider a relation r1(A, B, C), r2(C, D, E) and r3(F, G) with primary keys A, C and F respectively. Assume that r1 has 150 tupples, r2 has 100 tupples and r3 has 75 tupples. The number of resultant tuple in are ________.
Consider a relation r1(A, B, C), r2(C, D, E) and r3(F, G) with primary keys A, C and F respectively. Assume that r1 has 150 tupples, r2 has 100 tupples and r3 has 75 tupp...
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17
joins
what is different types of joins and what is difference between them ? please explain with example.
what is different types of joins and what is difference between them ?please explain with example.
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20
Test question
Consider the join of a relation R with a relation S. If R has 100 tuples and S has 9 tuples then the maximum and minimum sizes of the join respectively under referential integrity constraint: 9 and 0 9 and 9 9+100 and 0 9*100 and 9
Consider the join of a relation R with a relation S. If R has 100 tuples and S has 9 tuples then the maximum and minimum sizes of the join respectively under referential ...
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21
Tuples
Consider a relation R(A,B,C) with the following functional dependency AC→B .A can take 200 distinct values, B can take 100 distinct values and C can take 1000 distinct values. What is the maximum and minimum possible tuples of the self join of R on C?
Consider a relation R(A,B,C) with the following functional dependency AC→B .A can take 200 distinct values, B can take 100 distinct values and C can take 1000 distinct ...
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23
#DBMS What will be the Minimum Number of Tuples?
Say we have two relations R (a,b,c) and S (b,d,e). Now, R has 200 tuples and S has 300 tuples. What will be Minimum number of tuples when we do R ⋈ S ( ⋈ = Natural Join)?
Say we have two relations R (a,b,c) and S (b,d,e).Now, R has 200 tuples and S has 300 tuples. What will be Minimum number of tuples when we do R ⋈ S ( ⋈ = Natural Joi...
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2 votes
1 answer
24
Relational algebra
Consider the relations r1(P, Q, R) and r2(R, S, T) with primary keys P and R respectively. The relation r1 contains 2000 tuples and r2 contains 2500 tuples. The maximum size of the join r1⋈ r2 is equal to r2⋈ r1 true or false?
Consider the relations r1(P, Q, R) and r2(R, S, T) with primary keys P and R respectively. The relation r1 contains 2000 tuples and r2 contains 2500 tuples. The maximum s...
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25
DBMS SELF DOUBT
Let R and S be two relations with the following schema R(P−−,Q−−,R1,R2,R3) S(P−−,Q−−,S1,S2) where {P,Q} is the key for both schemas? R:{⟨"1","abc","p1","p2","p3"⟩, ⟨"2","xyz", ... ;,"q3"⟩ ⟨"2","def","q1","q2","q3"⟩ WHat is R *S? WHERE * IS NATURAL JOIN.
Let R and S be two relations with the following schemaR(P−−,Q−−,R1,R2,R3)S(P−−,Q−−,S1,S2)where {P,Q} is the key for both schemas?R:{⟨"1","abc","p1","p2"...
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26
relational algebra question
Given two union compatible relations R1(A,B) and R2(C,D), what is the result of the operation R1 ⋈ (A=C∨B=D)R2? R1∪R2 R1×R2 R1–R2 R1∩R2
Given two union compatible relations R1(A,B) and R2(C,D), what is the result of the operation R1 ⋈ (A=C∨B=D)R2?R1∪R2R1×R2R1–R2R1∩R2
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2 votes
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28
Relational Algebra
what is difference between full outer join and cross product?
what is difference between full outer join and cross product?
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