Oracle and PostgreSQL are two different databases and hence have their own SQL versions. Oracle as a commercial database has many built-in functions to provide user the flexibility to make data access simpler and development tasks easier.
While migrating to PostgreSQL database, many of the built-in functions are supported as is while many requires little changes. There are some Oracle functions that are not available in PostgreSQL or you do not have a direct function available. In those cases it is the job of the developer to write logic in PostgreSQL to migrate that functionality in PostgreSQL.
Through this chapter, we discuss on all frequently used Oracle functions and their equivalent functionality in PostgreSQL.