You can use the TOP n operator in these ways:
- The TOP n operator returns only a subset of the rows in the query result set. For example, this query returns 10 rows from the orders table:
SELECT TOP 10 * FROM orders;
- To obtain a subset of the data from an ordered set, specify the TOP n operator with an ORDER BY clause. For example, this query returns the last five orders shipped:
SELECT TOP 5 * FROM orders ORDER BY ship_date DESC;
- If the TOP n operator specifies a number greater than the number of rows in the query result set, then the query returns all of the rows in the query result set without returning an error.
- As the size of n increases, the performance of TOP n gradually degrades.
- You can use parameters to pass values for n from:
- CREATE MACRO, see Teradata Vantage™ SQL Data Definition Language Syntax and Examples, B035-1144.
- CREATE PROCEDURE (SQL Form), see Teradata Vantage™ SQL Data Definition Language Detailed Topics , B035-1184 .
- USING Request Modifier, see USING Request Modifier.