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Re: IF Statement - does nesting order matter?
Posted by: Peter Brawley
Date: November 14, 2017 10:31PM

> Can the true statement have multiple operations listed?

You mean you want the displayed result to show a list of the comparisons that went into it? You could write out the conditions as a matrix of 1 and 0s ...

select
  aquaculture_id,
  year_a,
  species_code_a,
  qty_prod,
  if( qty_prod=0, 1, 0 )                                    as 'zero',
  if( qty_prod < (0.5*max_prod_5, 1, 0 )                    as '< 50% 5yr avg',
  if( qty_prod between avg_prod_5 and avg_prod_1, 1, 0 )    as 'in 5-10 yr range',
  if( qty_prod >= avg_prod_10 and area_change_a > 0, 1, 0 ) as '>10 yr avg',
  if( area_change_a < 0, -1, if( area_change=0, 0, 1 )      as 'area_change'
from fao_aquaculture;

... then combine & describe them as desired in an outer query.

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Re: IF Statement - does nesting order matter?
November 14, 2017 10:31PM


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