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37 lines
985 B
SQL
37 lines
985 B
SQL
DROP TABLE IF EXISTS test_a;
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DROP TABLE IF EXISTS test_b;
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CREATE TABLE test_a
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(
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OldColumn String DEFAULT '',
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EventDate Date DEFAULT toDate(EventTime),
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EventTime DateTime
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) ENGINE = MergeTree(EventDate, EventTime, 8192);
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CREATE TABLE test_b
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(
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OldColumn String DEFAULT '',
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NewColumn String DEFAULT '',
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EventDate Date DEFAULT toDate(EventTime),
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EventTime DateTime
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) ENGINE = MergeTree(EventDate, EventTime, 8192);
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INSERT INTO test_a (OldColumn, EventTime) VALUES('1', now());
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INSERT INTO test_b (OldColumn, NewColumn, EventTime) VALUES('1', '1a', now());
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INSERT INTO test_b (OldColumn, NewColumn, EventTime) VALUES('2', '2a', now());
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ALTER TABLE test_a ADD COLUMN NewColumn String DEFAULT '' AFTER OldColumn;
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INSERT INTO test_a (OldColumn, NewColumn, EventTime) VALUES('2', '2a', now());
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SELECT NewColumn
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FROM test_a
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INNER JOIN
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(SELECT OldColumn, NewColumn FROM test_b) s
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Using OldColumn
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PREWHERE NewColumn != '';
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DROP TABLE test_a;
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DROP TABLE test_b;
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