Posted By: Jovo () on 'CZdatabases'
Title:     zajimavost
Date:      Wed Sep  4 19:49:54 2002

Ahoj.

  tab A                  tab B
  id                     id
  1                      1
  1                      2
  1                      3
  2
  2

A ted jak zjistit pocet zaznamu v B, ktere maji odkaz v tabulce A?

  SELECT COUNT(*) FROM a,b WHERE a.id = b.id 

vrati hodnotu 4. Nas sef nastesti nekde vyhrabal:

  SELECT COUNT(DISTINCT b.id) FROM a,b WHERE a.id = b.id

a to vrati 2 :-)  Je to Informix specific, nebo to funguje i jinde?
Jovo.

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