Teradata Parallel Data Pump

Chapter 3: Teradata TPump Commands
UPDATE Statement and Atomic Upsert
Example 3 (Error: unqualified primary index)
This example demonstrates an upsert statement that does not specify the primary index in the
WHERE clause.
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE SaleDate = '05/30/2005'
ELSE INSERT INTO Sales (10, '05/30/2005', 1);
When the primary index is not fully specified in the UPDATE of an upsert statement, an allrow
scan to find rows to update might result. This is again not the purpose of upsert, and an
error is returned to the user.
Example 4 (Error: missing ELSE)
This example demonstrates an upsert statement with a missing ELSE keyword.
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE (ItemNbr = 10 AND
SaleDate = '05/30/2005') INSERT INTO Sales (10, '05/30/2005', 1);
Example 5 (Error: INSERT-SELECT)
This example demonstrates an upsert statement that specifies INSERT … SELECT.
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE (ItemNbr = 10 AND
SaleDate = '05/30/2005') ELSE INSERT INTO Sales SELECT * FROM NewSales
WHERE (ItemNbr = 10 AND SaleDate = '05/30/2005');
The INSERT part of an upsert may not use a subquery to specify any of the inserted values. In
this case, a syntax error is returned.
Example 6 (Error: UPDATE-FROM)
This example demonstrates an upsert statement that specifies UPDATE-FROM.
UPDATE Sales FROM NewSales SET Sales.ItemCount = NewSales.ItemCount
WHERE Sales.ItemNbr = NewSales.ItemNbr ELSE INSERT INTO Sales (10, '05/
30/2005', 1);
The SET clause may not use a FROM clause table reference in the expression for the updated
value for a column, and an error is returned.
Example 7 (Error: UPDATE-WHERE SUBQUERIES)
This example demonstrates an upsert statement that specifies UPDATE-WHERE
SUBQUERIES.
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE ItemNbr IN (SELECT
ItemNbr FROM NewSales) ELSE INSERT INTO Sales (10, '05/30/2005', 1);
The WHERE clause of the UPDATE may not use a subquery for any purpose. In this case,
error ERRTEQUPSCOM is returned.
Example 8 (Error: UPDATE-PRIMARY INDEX)
This example demonstrates an upsert statement that tries to update a primary index value.
UPDATE Sales SET ItemNbr = 20 WHERE (ItemNbr = 10 AND SaleDate = '05/30/
2005') ELSE INSERT INTO Sales (20, '05/30/2005', 1);
Unreasonable updates or updates that change the primary index values are not allowed in an
upsert statement, and an error is returned.
Teradata Parallel Data Pump Reference 193