Oracle SQL Functions
- 1. 5. Functions in Oracle SQL. • Stored programs in Oracle that you can call from your SQL statements. • Used for various tasks such as data conversion, manipulation, aggregation etc. • Used extensively in SQL and PL/SQL programming. • Using PL/SQL, you can write your own custom functions. http://adata.guru
- 2. SQL syntax – Using a function function(input1, input2,..) -> output upper(‘Scott’) -> ‘SCOTT’ trunc(100.5346,2) -> 100.53 least(100,200) -> 100 Sysdate -> current date http://adata.guru
- 3. Types of functions Single row functions Multiple row functions http://adata.guru
- 4. Single row functions • Numeric functions – cos, sin, mod, round, trunc… • Character functions – Upper, lower, initcap, ltrim, rtrim, substr … • Conversion functions – to_date, to_char, asciistr, cast, convert … • DateTime functions – add_months, sysdate, current_date… and many more…. http://adata.guru
- 5. Multi-row functions • AVG • SUM • MIN • MAX • MEDIAN and more…. http://adata.guru
- 6. Dual table in Oracle • Dummy table present in Oracle installation by default • Can be used to test results of expressions even when there are no tables • The following commands would fail at a sqlplus prompt. – > 2+3 – > select 2+3 • We can use the dummy table dual to get the value of the expression we need. – > Select 2+3 from dual; – > 5 http://adata.guru