59 lines
2.5 KiB
Prolog
59 lines
2.5 KiB
Prolog
/*##############################################################################
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Copyright (C) 2011 HPCC Systems.
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All rights reserved. This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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############################################################################## */
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#option ('slidingJoins', true);
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namesRecord :=
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RECORD
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string20 surname;
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string10 forename;
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integer2 age;
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integer2 dadAge;
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integer2 mumAge;
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END;
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namesRecord2 :=
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record
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string10 extra;
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namesRecord;
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end;
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namesTable := dataset('x',namesRecord,FLAT);
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namesTable2 := dataset('y',namesRecord2,FLAT);
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integer2 aveAgeL(namesRecord l) := (l.dadAge+l.mumAge)/2;
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integer2 aveAgeR(namesRecord2 r) := (r.dadAge+r.mumAge)/2;
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// Standard join on a function of left and right
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output(join(namesTable, namesTable2, aveAgeL(left) = aveAgeR(right)));
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//Several simple examples of sliding join syntax
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output(join(namesTable, namesTable2, left.age >= right.age - 10 and left.age <= right.age +10));
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output(join(namesTable, namesTable2, left.age between right.age - 10 and right.age +10));
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output(join(namesTable, namesTable2, left.age between right.age + 10 and right.age +30));
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output(join(namesTable, namesTable2, left.age between (right.age + 20) - 10 and (right.age +20) + 10));
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output(join(namesTable, namesTable2, aveAgeL(left) between aveAgeR(right)+10 and aveAgeR(right)+40));
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//Same, but on strings. Also includes age to ensure sort is done by non-sliding before sliding.
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output(join(namesTable, namesTable2, left.surname between right.surname[1..10]+'AAAAAAAAAA' and right.surname[1..10]+'ZZZZZZZZZZ' and left.age=right.age));
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output(join(namesTable, namesTable2, left.surname between right.surname[1..10]+'AAAAAAAAAA' and right.surname[1..10]+'ZZZZZZZZZZ' and left.age=right.age,all));
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//This should not generate a self join
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output(join(namesTable, namesTable, left.age between right.age - 10 and right.age +10));
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