The column the DECODE function examines is named STATEĭECODE and NVL functions Example Explanation of an example of the DECODE function Here are the results when using the CUSTOMER table in the pet store schema.For your information, this name is the column alias.It applies to all rows where the value in STATE is neither 'HI' nor 'AK.' In these cases, the value shown here gets returned by the DECODE function. If STATE equals 'AK,' the DECODE function returns this value.The second case is considered if STATE does not contain 'HI.' Here, STATE is compared to 'AK.'.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 diagram below shows an example of DECODE for the state of Hawaii HI. 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,, ) Sql Plus Environment Lesson 8 DECODE and NVL functions Objective Modify query results using the DECODE and NVL functions DECODE Function in Oracle.
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