12/04/2013

Search Query Builder confusing results


Search Query Builder confusing results

I was never good in maths nor programming but still I wanted to get to the bottom of the mysteries in the use of operators in the Search Query Builder. The study area was KAJANG LOCAL PLAN where the attribute table identified a total of 53,189 features. Applying SQL for Field 'Semasa' to Value 'Industri', the results obtained were as follows:

  1. Semasa = Industri results 171
  2. Semasa < Industri results 648
  3. Semasa > Industri results 52,536
  4. Semasa LIKE Industri results 171
  5. Semasa % Industri results unknown operator:7
  6. Semasa IN Industri results syntax error, unexpected STRING,expecting '('
  7. Semasa NOT IN Industri results syntax error, unexpected STRING,expecting '('
  8. Semasa <= Industri results 477
  9. Semasa >= Industri results 52,536
  10. Semasa != Industri results 52,842
  11. Semasa ILIKE Industri results 171
  12. Semasa AND Industri results syntax error, unexpected AND, expecting $end
  13. Semasa OR Industri results syntax error, expected OR, expecting $end
  14. Semasa NOT Industri results syntax error, expected STRING, expecting IN
Confusing... to me, at least:
  • If total polygons are 53,189 features and Semasa = Industri is 171 therefore, the balance should be 53,018 features yet this does not appear in any result. Why?
  • If the balance is not 53,018 features, what does the results 52,536 and 52, 842 stand for?
  • If Semasa != Industri results 52,842, what does the result 648 and 477 stand for?

I'm lost! I think if I had taken up programming, I would have definitely failed.

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