B Supported SQL Syntax and Functions

This appendix contains the following sections:

Supported SQL Statements
Oracle Functions

B.1 Supported SQL Statements

With a few exceptions, the gateway provides full support for Oracle DELETE, INSERT, SELECT, and UPDATE statements.

The gateway does not support Oracle data definition language (DDL) statements. No form of the Oracle ALTER, CREATE, DROP, GRANT, or TRUNCATE statements can be used. Instead, use the pass-through feature of the gateway if you need to use DDL statements against the Teradata database.

See Also:

Oracle Database SQL Reference for a detailed descriptions of keywords, parameters, and options.

B.1.1 DELETE

The DELETE statement is fully supported. However, only Oracle functions supported by Teradata can be used.

See Also:

"Functions Supported by Teradata" for a list of supported functions.

B.1.2 INSERT

The INSERT statement is fully supported. However, only Oracle functions supported by Teradata can be used.

See Also:

"Functions Supported by Teradata" for a list of supported functions.

B.1.3 SELECT

The SELECT statement is fully supported, with these exceptions:

CONNECT BY condition
NOWAIT
START WITH condition
WHERE CURRENT OF

B.1.4 UPDATE

The UPDATE statement is fully supported. However, only Oracle functions supported by Teradata can be used. Also, you cannot have SQL statements in the subquery that refer to the same table name in the outer query. Subqueries are not supported in the SET clause.

See Also:

"Functions Supported by Teradata" for a list of supported functions.

B.2 Oracle Functions

All functions are evaluated by the Teradata database after the gateway has converted them to Teradata SQL.

B.2.1 Functions Not Supported by Teradata

Oracle SQL functions with no equivalent function in Teradata are not supported in DELETE, INSERT, or UPDATE statements, but are evaluated by the Oracle database server if the statement is a SELECT statement. That is, the Oracle database server performs post-processing of SELECT statements sent to the gateway.

If an unsupported function is used in a DELETE, INSERT, or UPDATE, statement, the following Oracle error occurs:

ORA-02070: database db_link_name does not support function in this context

B.2.2 Functions Supported by Teradata

The gateway translates the following Oracle database server functions in SQL statements to their equivalent Teradata functions:

Arithmetic Operators
Comparison Operators
Group Functions
String Functions
Other Functions

B.2.2.1 Arithmetic Operators

Oracle	Teradata
+	+
-	-
*	*
/	/

B.2.2.2 Comparison Operators

Oracle	Teradata
=	=
>	>
<	<
>=	>=
<=	<=
<>, !=, ^=	<>, !=
IS NOT NULL	IS NOT NULL
IS NULL	IS NULL

B.2.2.3 Group Functions

Oracle	Teradata
AVG	AVG
COUNT	COUNT
MAX	MAX
MIN	MIN
SUM	SUM

B.2.2.4 String Functions

Oracle	Teradata
\|\|	CONCAT
INSTR	LOCATE
LENGTH	LENGTH
SUBSTR (second argument cannot be a negative number)	SUBSTRING
UPPER	UCASE

B.2.2.5 Other Functions

Oracle	Teradata
ABS	ABS
EXP	EXP
LOG(a, b)	LOG10(b) / LOG10(a)
POWER	**
SQRT	SQRT