Built-In FunctionsThe PL/SQL provides a lot of powerful functions to help you to manipulate the data. These built-in functions fall into the categories as shown below:error reportingnumbercharacterdatatype conversiondateobject referencemiscellaneousThe table shows the functions in each and every category. You can use all the functions in the SQL statements except the error-reporting functions SQLCODE and SQLERRM. You can also use all the functions in the procedural statements except the miscellaneous functions like DECODE, DUMP, & VSIZE.The SQL aggregate functions such as AVG, GROUPING, COUNT, STDDEV, MIN, MAX, SUM, and VARIANCE are not built into PL/SQL. However, you can use them in the SQL statements (but not in the procedural statements).
Table: Built-in Functions