Android Question Equivalence of 2 SQL Commands without physically running them on SAME table and comparing results

beelze69 said:

Hi,

Is there a logic to check if two Sql Queries would yield same result.

For example:

We know that

Query1: Select Name, Cadre, Age, Salary FROM myTable WHERE Name ='Alice' AND Cadre in ('A','B','C','D') and AGE <=35 and Salary >=40000

Query2: SELECT Name,Cadre, Age, Salary FROM myTable WHERE Name='Alice' AND (Cadre ='A' or Cadre ='B' or Cadre = 'C' or Cadre='D') AND AGE<=35 AND SALARY>=40000

- would yield SAME result if both are run on the SAME table.

Now is there a way to find this WITHOUT ACTUALLY RUNNING THE QUERIES ON THE TABLES and comparing their results ?

Meaning, I want to develop a function which would be used like:

if isEquivalent(Query1,Query2) then
Msgbox("Both the functions would return same result")
else
Msgbox("They are not equivalent queries")
end if

Note:
The above function isEquivalent must NOT make use of any table to check this since we (humans) do not need a table to check that they will yield the same result ! Looking at the query itself we know that it will give the SAME result when run on the SAME table...


Ps. help !

Thanks.

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mangojack said:

Is this of any use .. It appears the might be an API you could use . http://cosette.cs.washington.edu/ .

ps: I'm scratching my head wondering why you need this .. but obviously theres a reason

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