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sql server: update table random

开发者 https://www.devze.com 2023-02-18 11:14 出处:网络
I have a table with 2 columns of sample data. Column1 is the primary key and is tied with several other tables. Column 2 is an int that randomly ranges from 1 to 5. I\'m looking for a way to change th

I have a table with 2 columns of sample data. Column1 is the primary key and is tied with several other tables. Column 2 is an int that randomly ranges from 1 to 5. I'm looking for a way to change the data in place in column 2 so that it ranges from 1 to 8. I'm not an expert in SQL and I was wondering what would be the easiest way to do this. There are about 3400 records so I guess I could go in manually and type numbers at random but I'm sure there'开发者_StackOverflow中文版s a better way to do it.

Any suggestions?

Thanks.


You can use RAND() function. Well, you could use it if it worked as someone would suppose.

This will NOT work in Sql-Server:

UPDATE tableT
  SET column2 = CAST(1 + (RAND() * 8) AS INT)
;

But this does:

UPDATE tableT
  SET column2 = 1 + 8 * RAND( CHECKSUM( NEWID() ) )
;


rand() is only evaluated once per query. So all your column2 values will be the same.

For SQL Server 2008 you can use

UPDATE tableT
  SET column2 = 1+ (CRYPT_GEN_RANDOM(1) % 8)

For earlier versions

UPDATE tableT
  SET column2 = 1+ (abs(checksum(NewId())) % 8)


I think that your answer would actually return NINE, right?

I'd try this instead

UPDATE tableT SET column2 = CAST(1 + (RAND() * 7) AS INT);

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