SQL: detecting differences in sums between two tables? -

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it seems simple enough: have 2 votes , want see states have different numbers of votes. individually, it's easy:

select state, sum(votes) votes_a group state;  select state, sum(votes) votes_b group state;

how query state, votes_a, votes_b states have different results?

try join:

select     totals_a.state,     totals_a.total_votes,     totals_b.total_votes (     select state, sum(votes) total_votes     votes_a     group state ) totals_a join (     select state, sum(votes) total_votes     votes_b     group state ) totals_b on totals_a.state = totals_b.state totals_a.total_votes <> totals_b.total_votes

note miss states received 0 votes in 1 of tables. fix use full outer join (assuming database supports feature) , check nulls.


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