Consider the following schemas. R1=(A, B,C)
R2=(A,E,F)
R3-(E,D)
Write both relational algebra and SQL expressions for the following queries:
List the Sum of D’s for each A, where the value of B is 25.
List A and E that has the largest D value of all As.
List C and F that of C does not start with 'h'
List C and D that has value of F less than 20
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