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34 строки
637 B
Plaintext
34 строки
637 B
Plaintext
2025
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Otus - Small Tricks of Group By 0:00 of 1:31:23
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https://www.youtube.com/watch?v=yj27kupwrMQ
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having
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(where works before aggregations calculation)
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https://www.postgresql.org/docs/current/functions-aggregate.html
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https://www.postgresql.org/docs/current/queries-table-expressions.html#QUERIES-GROUP
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=> SELECT * FROM test1;
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x | y
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---+---
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a | 3
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c | 2
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b | 5
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a | 1
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(4 rows)
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=> SELECT x, sum(y) FROM test1 GROUP BY x;
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x | sum
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---+-----
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a | 4
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b | 5
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c | 2
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(3 rows)
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select field1, field2, count(*) as cnt
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from tbl
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where field-date >= now() - '30 days'::interval and ...
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group by field1, field2
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having count(*) > 1;
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