Query System Features October 2006 How-to Guide SAP NetWeaver ‘04 How To… Use Query Functions with the Distributed Query Engine (DQE) Version 3.00 – April 2006 Applicable Releases: SAP NetWeaver ’04 © Copyright 2006 SAP AG. All rights reserved. contained in this document serves informational purposes only. National product specifications may vary. No part of this publication may be reproduced or transmitted in any form or for any purpose These materials are subject to change without notice. These without the express permission of SAP AG. The materials are provided by SAP AG and its affiliated companies information contained herein may be changed ("SAP Group") for informational purposes without prior notice. only, without representation or warranty of any kind, and SAP Group shall not be liable for errors or omissions with respect to Some software products marketed by SAP AG and the materials. 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Data 2 Contents Query System Features................................................................................................................... 4 Query Constructs.................................................................................................................. 4 Supported SQL Constructs ............................................................................................ 4 UNSUPPORTED SQL CONSTRUCTS................................................................................ 6 METADATA IDENTIFIERS................................................................................................... 6 Prohibited Characters in Identifiers ................................................................................ 8 JOINS ................................................................................................................................... 8 Explicit Joins................................................................................................................... 8 Join Processing .............................................................................................................. 8 Dependent Join .............................................................................................................. 8 Implicit Type Conversions During Join........................................................................... 9 EXPRESSIONS .................................................................................................................... 9 DATATYPES ........................................................................................................................ 9 DATATYPE CONVERSIONS ............................................................................................. 11 FUNCTIONS.......................................................................................................................14 Numeric ........................................................................................................................ 14 String 16 Type 19 Miscellaneous............................................................................................................... 19 Query Grammar............................................................................................................................. 21 Notation............................................................................................................................... 21 Special Terminals ...............................................................................................................21 Non-Terminals .................................................................................................................... 22 3 Query System Features This booklet is designed to serve as a reference for developers of SAP NetWeaver ’04 portal content. It is meant to supply the technical information necessary for content that retrieves data from back-end applications using the Distributed Query Engine (DQE). Query Constructs Supported SQL Constructs SQL queries start with the SELECT keyword and are often referred to as “SELECT statements” as well. The SAP Distributed Query Engine (DQE) supports most but not all of the standard SQL query constructs. Many of these features can be combined to execute complex queries against the DQE service. The following list of features gives an overview of the kinds of queries that can be executed using the Distributed Query Engine. Nearly all of these features follow standard SQL syntax and functionality. Please refer to your preferred standard SQL reference for detailed information on how to use these features. The ordering of the clauses in a query are as follows: SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY, and OPTION. All of these clauses are optional except SELECT and FROM, which are required. SELECT Clause Features • SELECT * • SELECT table.* • SELECT expression, … • SELECT expression AS name • SELECT DISTINCT expression • SELECT COUNT(*) • SELECT COUNT(expression), COUNT(DISTINCT expression) • SELECT SUM(expression), SUM (DISTINCT expression) • SELECT AVG(expression), AVG (DISTINCT expression) • SELECT MIN(expression), MIN (DISTINCT expression) • SELECT MAX(expression), MAX (DISTINCT expression) FROM Clause Features • FROM table • FROM table AS name • FROM table AS name1, table AS name2 • FROM table1 JOIN table2 ON join-criteria • FROM table1 CROSS JOIN table2 • FROM table1 RIGHT OUTER JOIN table2 ON join-criteria • FROM table1 LEFT OUTER JOIN table2 ON join-criteria • FROM table1 FULL OUTER JOIN table2 ON join-criteria 4 • FROM (table1 JOIN table2 ON join-criteria) JOIN table3 ON join-criteria • FROM (SELECT …) AS name WHERE Clause Features • WHERE expression1 = expression2 • WHERE expression1 <> expression2 • WHERE expression1 < expression2 • WHERE expression1 <= expression2 • WHERE expression1 > expression2 • WHERE expression1 >= expression2 • WHERE expression1 LIKE expression2 • WHERE expression1 LIKE expression2 ESCAPE character • WHERE expression1 IN (expression2, …) • WHERE expression1 IN (SELECT expression2…) • WHERE expression1 IS NULL • WHERE NOT criteria • WHERE criteria1 AND criteria2 AND … • WHERE criteria1