If STATE is equal to 'HI', then the DECODE function returns the literal shown here.The first case looks at the value in STATE and compares it to this value (the literal 'HI').The column the DECODE function examines is named STATE.The MouseOver below shows an example of DECODE. The final value is used when col1's value does not match any of the cases. ,else)Īdd as many case and value pairs as you need. DECODE(value, if1, then1, if2, then2, if3, then3. Traditional Programming LogicIn programming and logic, a common construction of a problem is in the pattern if (temp >32)īasic structure and usage of DECODE. If there is no match, the function returns 'Unknown'. If a match is found, the corresponding job title is returned. In this example, the DECODE function evaluates the job_code column, comparing it with the specified search values ('MGR', 'DEV', and 'HR'). SELECT first_name || ' ' || last_name AS full_name, Here is a sample query using the DECODE function: We want to retrieve the full names of all employees along with a description of their job titles. Suppose we have a table named employees with the following columns: employee_id, first_name, last_name, and job_code. If no match is found and a default value is provided, the function returns the default value otherwise, it returns NULL. If a match is found, it returns the corresponding resultN value. The DECODE function compares the expression with each searchN value sequentially. default: Optional parameter that specifies the value to be returned if no match is found.resultN: The corresponding result value to be returned if the expression matches the search value.searchN: The search value to compare with the expression.expression: The value or column to be evaluated.The syntax for the DECODE function is as follows:ĭECODE(expression, search1, result1,, ) In essence, it provides a convenient way to perform if-then-else logic within a query, thus enabling users to manipulate and transform data as per specific conditions. The primary purpose of the DECODE function is to evaluate a given expression, compare it to a set of search values, and return the corresponding result value based on the match. It is similar to the CASE statement, but it offers a more compact syntax, making it a popular choice for simplifying complex queries and improving code readability. The DECODE function in Oracle is a versatile and powerful tool that allows users to perform conditional transformations on data within an SQL query. What is the purpose of the DECODE Function in Oracle? Sql Plus Environment Lesson 8 DECODE and NVL functions Objective Modify query results using the DECODE and NVL functions DECODE Function in Oracle.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |