Oracle Functions

B.2 Oracle Functions

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

The exception is the TO_DATE function, which is evaluated by the gateway.

Functions Not Supported by SQL Server
Oracle SQL functions with no equivalent function in SQL Server are not supported in DELETE, INSERT, or UPDATE statements, but are evaluated by the Oracle database if the statement is a SELECT statement.
Functions Supported by SQL Server
These topics describe the functions supported by Oracle Database Gateway for SQL Server.
Functions Supported by the Gateway
If an Oracle function has no equivalent function in SQL Server, the Oracle function is not translated into the SQL statement and must be post-processed if the SQL statement is a SELECT.

Parent topic: Supported SQL Syntax and Functions

B.2.1 Functions Not Supported by SQL Server

Oracle SQL functions with no equivalent function in SQL Server are not supported in DELETE, INSERT, or UPDATE statements, but are evaluated by the Oracle database if the statement is a SELECT statement.

That is, the Oracle database 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

Parent topic: Oracle Functions

B.2.2 Functions Supported by SQL Server

These topics describe the functions supported by Oracle Database Gateway for SQL Server.

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

Arithmetic Operators
Arithmetic operators supported by Oracle Database Gateway for SQL Server.
Comparison Operators
Comparison operators supported by Oracle Database Gateway for SQL Server.
Pattern Matching
Pattern matching using Oracle Database Gateway for SQL Server.
Group Functions
Group functions supported by Oracle Database Gateway for SQL Server.
String Functions
String functions supported by Oracle Database Gateway for SQL Server.
Other Functions
Additional functions supported by Oracle Database Gateway for SQL Server.

Parent topic: Oracle Functions

B.2.2.1 Arithmetic Operators

Arithmetic operators supported by Oracle Database Gateway for SQL Server.

Oracle	SQL Server
`+`	`+`
`-`	`-`
`*`	`*`
`/`	`/`

Parent topic: Functions Supported by SQL Server

B.2.2.2 Comparison Operators

Comparison operators supported by Oracle Database Gateway for SQL Server.

Oracle	SQL Server
`=`	`=`
`>`	`>`
`<`	`<`
`>=`	`>=`
`<=`	`<=`
`<>, !=, ^=`	`<>`
`IS NOT NULL`	`IS NOT NULL`
`IS NULL`	`IS NULL`

Parent topic: Functions Supported by SQL Server

B.2.2.3 Pattern Matching

Pattern matching using Oracle Database Gateway for SQL Server.

Oracle	SQL Server
`LIKE`	`LIKE`
`NOT LIKE`	`NOT LIKE`

Parent topic: Functions Supported by SQL Server

B.2.2.4 Group Functions

Group functions supported by Oracle Database Gateway for SQL Server.

Oracle	SQL Server
`AVG`	`AVG`
`COUNT`	`COUNT`
`MAX`	`MAX`
`MIN`	`MIN`
`SUM`	`SUM`

Parent topic: Functions Supported by SQL Server

B.2.2.5 String Functions

String functions supported by Oracle Database Gateway for SQL Server.

Oracle	SQL Server
`\|\|, CONCAT`	`+` `(expression1` `+` `expression2)`
`ASCII`	`ASCII`
`CHR`	`CHAR`
`INSTR` (with two arguments)	`CHARINDEX`
`LENGTH ()`	`LEN ()`
`LENGTHB ()`	`DATALENGTH ()`
`LENGTHC ()`	`LEN ()`
`LOWER`	`LOWER`
`LTRIM`	`LTRIM`
`RTRIM`	`RTRIM`
`SUBSTR` (second argument cannot be a negative number)	`SUBSTRING`
`UPPER`	`UPPER`

Parent topic: Functions Supported by SQL Server

B.2.2.6 Other Functions

Additional functions supported by Oracle Database Gateway for SQL Server.

Oracle	SQL Server
`ABS`	`ABS`
`CEIL`	`CEILING`
`COS`	`COS`
`EXP`	`EXP`
`FLOOR`	`FLOOR`
`LN`	`LOG`
`LOG`	`LOG10`
`MOD`	`%`
`NOT NVL`	`IS NOT NULL`
`NVL`	`IS NULL`
`POWER`	`POWER`
`ROUND`	`ROUND`
`SIN`	`SIN`
`SQRT`	`SQRT`
`TAN`	`TAN`

Parent topic: Functions Supported by SQL Server

B.2.3 Functions Supported by the Gateway

If an Oracle function has no equivalent function in SQL Server, the Oracle function is not translated into the SQL statement and must be post-processed if the SQL statement is a SELECT.

The gateway, however, does support the TO_DATE function equivalent in SQL Server, as follows:

TO_DATE(date_string | date_column)

where:

date_string is converted to a string with the following format:
```
yyyy-mm-dd hh:mi:ss.fff
```
Note:
Supply the date string with the same format as the result (that is, yyyyy-mm-dd hh:mi:ss.fff).
date_column is a column with a date data type. It is converted to a parameter with a timestamp data type.

Parent topic: Oracle Functions