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Re: Problem with this Query
Posted by: Peter Brawley
Date: June 23, 2021 09:51AM

1 How can it be meaningful to try to match with the "father" if he's not the father!?

2 Your Where subclauses referencing mother_results and father_results effectively turn your Left self-Joins into Inner Joins. Since you don't know what's there till you see it, I suggest you start with a more inclusive query to see what's there, eg ...

  dna_results.allele_1 as son_a1,
  dna_results.allele_2 as son_a2,
  mother_results.allele_1 as mother_a1,
  mother_results.allele_2 as mother_a2,
  father_results.allele_1 as father_a1,
  father_results.allele_2 as father_a2,
from dna_results
left join snp_markers                   on dna_results.snp_marker_id =
left join dna_results as mother_results on snp_results.snp_marker_id = mother_results.snp_marker_id
left join dna_results as father_results on snp_results.snp_marker_id = father_results.snp_marker_id
where dna_results.dna_result_id = 85396         -- son dna result id
order by dna_results.snp_marker_id asc;

... then tailor your query accordingly.

3 It may be difficult or impossible to get all the info you want from one query. Remember, there are occasions when multiple queries offer the best solution.

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Re: Problem with this Query
June 23, 2021 09:51AM

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