HASHROW, HASHBUCKET, HASHAMP in Teradata

1.http://www.teradatahelp.com/2010/09/how-can-you-view-data-distribution-in.html


1. http://rajgopal-gurrapushala.blogspot.com/2012/11/types-of-hash-functions-used-in-teradata_734.html
Create Table emp
(
ID BIGINT NOT NULL GENERATED BY DEFAULT AS IDENTITY
           (START WITH 1
            INCREMENT BY 1
            MINVALUE -999999999999999999
            MAXVALUE 999999999999999999
            NO CYCLE),
empname varchar(20),
empdept varchar(10)
)
PRIMARY INDEX(ID);
insert into emp(empname,empdept) values('D','X');
insert into emp(empname,empdept) values('C','X');
insert into emp(empname,empdept) values('B','X');
insert into emp(empname,empdept) values('A','X');
insert into emp(empname,empdept) values('A','X');
SELECT
            HASHROW (EMP.empname)   AS "Hash Value"
            , HASHBUCKET (HASHROW (EMP.empname)) AS "Bucket Num"
            , HASHAMP (HASHBUCKET (HASHROW (EMP.empname))) AS "AMP Num"
            , HASHBAKAMP (HASHBUCKET (HASHROW (EMP.empname)))  AS "AMP Fallback Num"
            ,EMP.empname
FROM EMP;