Discussions
Categories
- 385.5K All Categories
- 5.1K Data
- 2.5K Big Data Appliance
- 2.5K Data Science
- 453.4K Databases
- 223.2K General Database Discussions
- 3.8K Java and JavaScript in the Database
- 47 Multilingual Engine
- 606 MySQL Community Space
- 486 NoSQL Database
- 7.9K Oracle Database Express Edition (XE)
- 3.2K ORDS, SODA & JSON in the Database
- 585 SQLcl
- 4K SQL Developer Data Modeler
- 188K SQL & PL/SQL
- 21.5K SQL Developer
- 46 Data Integration
- 46 GoldenGate
- 298.4K Development
- 4 Application Development
- 20 Developer Projects
- 166 Programming Languages
- 295K Development Tools
- 150 DevOps
- 3.1K QA/Testing
- 646.7K Java
- 37 Java Learning Subscription
- 37.1K Database Connectivity
- 201 Java Community Process
- 108 Java 25
- 22.2K Java APIs
- 138.3K Java Development Tools
- 165.4K Java EE (Java Enterprise Edition)
- 22 Java Essentials
- 176 Java 8 Questions
- 86K Java Programming
- 82 Java Puzzle Ball
- 65.1K New To Java
- 1.7K Training / Learning / Certification
- 13.8K Java HotSpot Virtual Machine
- 94.3K Java SE
- 13.8K Java Security
- 208 Java User Groups
- 25 JavaScript - Nashorn
- Programs
- 667 LiveLabs
- 41 Workshops
- 10.3K Software
- 6.7K Berkeley DB Family
- 3.6K JHeadstart
- 6K Other Languages
- 2.3K Chinese
- 207 Deutsche Oracle Community
- 1.1K Español
- 1.9K Japanese
- 474 Portuguese
Implementing SUBSTRING and POSITION standard SQL string functions

I compared string functions in 5 different RDBMS: PostgreSQL, MySQL, Oracle, SQL Server and SQLite, and also in the ANSI SQL Standard. There are large differences among different RDBMS, and I propose to reduce them a little bit.
The SQL Standard defines, among others, these functions operating on text strings:
SUBSTRING(s FROM start [FOR length]) POSITION(s2 IN s)
They are already implemented by PostgreSQL and MySQL. I propose to implement these 2 functions in Oracle as well. Currently, Oracle implements the following functions that work identically to the SQL Standard:
SUBSTR(s, start [,length]) INSTR(s, s2)
For more information about comparing implementations of the scalar functions, click here: https://github.com/iwis/SQL-notes/blob/master/Functions.txt
Comments
-
The last time I checked the ANSI standard allowed each vendor to name the function as they like. But those ISO documents are always difficult to read, so I might be mistaken. From that perspective Oracle is ANSI compliant. However having an ALIAS and a slightly different syntax, would not hurt as long as the old syntax still works.