RazorSQL ships with a built in relational database engine that is up and running out of the box and requires no end user administration. Any other JDBC or ODBC (Windows only) compliant database is also supported. Here we discuss how DECODE() function works in SQL with query examples for understanding better.RazorSQL is a SQL database query tool, SQL editor, database browser, and administration tool with support for all major databases and built in connection capabilities for DB2, Derby, Firebird, FrontBase, HSQLDB, Informix, Microsoft SQL Server, MySQL, OpenBase, Oracle, PostgreSQL, SimpleDB, SQL Anywhere, SQLite, SQL Azure, and Sybase. It is a built-in function in ORACLE / PL SQL database management servers. The function is a close relative of CASE statements. In the above example, we have performed the following task using the DECODE function and have then ordered the result set by college_id.ĭECODE function is used to perform procedural IF-THEN-ELSE logic in SQL. SQL query to categories college fees into affordable and expensive for an Indian student, considering everything above $ 10000 as expensive.ĭECODE(fees,10000,'Affordable','Expensive')
IF college_name = 'Massachusetts Institute of Technology'ĮLSE IF college_name = 'California Institute of Technology' In the above example, we have performed the following IF-THEN-ELSE logic statements and then ordered the entire result set by college_id. 'MIT','California Institute of Technology','CalTech','IIT') as college_name SELECT college_id, DECODE(college_name,'Massachusetts Institute of Technology', SQL query to illustrate abbreviation of college names based on the available data using DECODE function. Simple illustration of above mentioned DECODE function is as follows: In this example, we have performed a simple SQL task for categorizing colleges based on their location. Simple SQL query to illustrate use of DECODE function.ĭECODE (college_id, 10003,'Massachusetts, USA', The data in the “college_details” table after performing the above mentioned INSERT operations looks something as shown below: INSERT INTO college_details VALUES (10003, 'Massachusetts Institute of Technology', 'Massachusetts,India', 51520) INSERT INTO college_details VALUES (10004, 'California Institute of Technology', 'California ,USA', 60520) INSERT INTO college_details VALUES (10002, 'Indian Institute of Technology Bombay', 'Mumbai,India', 10000) INSERT INTO college_details VALUES (10001, 'Indian Institute of Technology Roorkee', 'Roorkee,India', 10000) We can use the following insert statements. Having created the table, let us now input some random data in it to work with in the subsequent exercises. We can use the following SQL CREATE TABLE statement to perform the task.Ĭollege_name character varying(255) NOT NULL,Ĭollege_location character varying(255) NOT NULL, Let us first create a ‘college_details’ table which contains college id, college name, location and fees for demonstration purposes. The simple illustration of the above mentioned decode function is as follows: The functionality of DECODE in ORACLE with following flowchart. And it finally converts back the data_type of result to the data_type of the expression. The DECODE function automatically converts or casts the expression to the data type of the first search argument or search_1. If it’s FALSE then DEFAULT value is returned. The first step is comparison of expression and search_1, if the expression = search_1 is TRUE then result_1 is returned. We can use the DECODE function as a part of the SELECT statement, ORDER BY etc. It is more or less like the ELSE statement in IF-THEN-ELSE. default: default argument holds the default value.For example, if expression = search_1 then result will be result_1. result_1, result_2, …, result_n: These arguments hold the result to be returned when the given comparison returns true.
search_n: These are the values to be searched for and then compared with the expression argument. expression: expression argument is the value which is to be searched and compared with.The parameters used in the above mentioned syntax are: The basic syntax for writing DECODE function in SQL is as follows:ĭECODE (expression, search_1, result_1. Hadoop, Data Science, Statistics & others