R1 := σC (R2)

C is a condition (as in “if” statements) that refers to attributes of R2.

R1 is all those tuples of R2 that satisfy C.

selection

milk milk_type price Al-marai Full_Fat 2.50 Al-marai Refresh 2.75 Lancor Full_Fat 2.50 Lancor Refresh 3.00

Prices := σ milk=‘Al-marai’(Sells):

milk milk_type Al-marai Full_Fat Al-marai Refresh

Sells

price 2.50 2.75

Display only the milk Al-marai

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For example, the operation SID=101 selects all tuples in the input relation which have the value 101 in column SID.

Exercise 1- selection Exercise 2- selection

Select only A which has value one

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For example, the operation SID=101 selects all tuples in the input relation which have the value 101 in column SID.

Selection – exercise 1 & 2 Result

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Selection – exercise 3

Select the employee whose age is less than 30 or salary is greater than 4000

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Selection – exercise 3 solution

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Selection – exercise 4

Select where placeofbirth and residence place have same value or same place.

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Selection – exercise 4 solution

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Selection – exercise 5

Select where person whose age is greater than or equal to 34

Select the person whose age and weight should be same

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Selection – exercise 5 solution

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Selection – exercise 6

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Selection – exercise 6 solution

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Selection – exercise 7

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Selection – exercise 8

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Selection – exercise 8 solution

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