Substitute for Function STUFF (SQL Server) in AWS redshift-CodePudding

I have to replace first 3 digits of a column to a fix first 3 digits (123) Working SQL Server code. (Not working on AWS RedShift)

Code:

Select 
Stuff (ColName,1,3,'123')as NewColName
From DataBase.dbo.TableName

eg 1 -Input --- 8010001802000000000209092396---output -1230001802000000000209092396 eg 2 -Input --- 555209092396- --output -123209092396

it should replace the first 3 digits to 123 irrespective of its length.

Please advice anything that is supported in AWS Redshift.

yet trying using substring and repalce.

CodePudding user response：

Got this and worked --Using Substring and concat

Select cast('123' substring(ColName,4,LEN(ColName)) as numeric (28)) as NewColName From DataBase.dbo.TableName

CodePudding user response：

I see that AWS RedShift was based on an old version of Postgres, and I looked up the SUBSTRING function for you (https://docs.aws.amazon.com/redshift/latest/dg/r_SUBSTRING.html), which is pretty forgiving of its argument values.

In this sample in Transact-SQL, and as documented for RedShift, the third argument of SUBSTRING can be much longer than the actual strings without causing an error. In Transact-SQL, even the second argument is "forgiving" if it starts after the end of the actual string:

;
WITH RawData AS
     (SELECT * FROM (VALUES ('8010001802000000000209092396'),
                            ('555209092396'),
                            ('AB')
                    ) AS X(InputString)
     )
     SELECT InputString, '123'   SUBSTRING(InputString, 4, 1000) AS OutputString
            FROM RawData

InputString                     OutputString
8010001802000000000209092396    1230001802000000000209092396
555209092396                    123209092396
AB                              123

As it appears that the concatenation operator in Redshift is ||, I think your expression will be very close to:

'123' || SUBSTRING(InputString, 4, 1000)