550_____________________________________________ 10

      Pers.  

SELECT count(*) as Uexl FROM Pers WHERE =' 

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SELECT count(DISTINCT Dep) FROM Pers

   ,    Dep  Pers.

 (<>), (<>), avg(<none>), sum(<none>) 
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SELECT min(Year_b), max(Year_b), avg(Year_b) FROM Pers
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SELECT min(1999-Year_b), max(1999-Year_b), avg(1999-Year_b)
FROM Pers WHERE Dep=''

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SELECT 1999-(min(Year_b)+max(Year_b))/2 FROM Pers WHERE
Dep=''

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SELECT Fam, max(Year_b) FROM Pers

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SELECT Dep , count(*) _ FROM Pers GROUP BY Dep

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