Regular Expression in Oracle SQL Regular Expression in Oracle SQL is a pattern matching technique to retrieve sort of data based on the conditions given in Oracle database. Pattern Matching is similar to functions like, replace, substring and in string which are previously seen topics. At the end of this article there will be certain task to practice for this Regular Expressions. It is very important to be very clear about this topic, this are very helpful for many interview Questions. Using regular expressions with Oracle Database: Overview Regular Expression is one of the easiest way to learn with clear understanding if one are familiar with the below Basic string matching patterns, Quantifiers, Meta characters, Functions etc. Note : The above points should understand clearly means it will be very easy to write a query. Basic String Matching with Regular Expressions | Either or () Group \ Escape ^ Start $ Stop Literals of regular expression in oracle sql [ a b c ] a, b, c [^ a