Difference between revisions of "Oracle/Shuffle data"
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The individual random values are used so that both columns are shuffled separately (else they would stay together as a pair). | The individual random values are used so that both columns are shuffled separately (else they would stay together as a pair). | ||
'''Note: NULL values will be lost (will be set to the same random value).''' | |||
Revision as of 12:55, 5 May 2011
The following statement shuffles to content of columns (name and street):
-- shuffle the columns name and street (separately)
MERGE INTO address t1
USING (SELECT address_id,
nvl(lead(name) over (order by dbms_random.value(1,1)),
first_value(name) over (order by dbms_random.value(1,1))) name,
nvl(lead(street) over (order by dbms_random.value(2,2)),
first_value(street) over (order by dbms_random.value(2,2))) street
FROM address) t2
ON (t1.address_id = t2.address_id)
WHEN matched THEN
UPDATE
SET t1.name = t2.name, t1.street = t2.street;
The individual random values are used so that both columns are shuffled separately (else they would stay together as a pair).
Note: NULL values will be lost (will be set to the same random value).