How to use oracle decode function in mysql

In MySQL, you can use CASE expressions to implement functions similar to Oracle's DECODE function: determine conditions and return values; use CASE expressions to list conditions and return values; add ELSE statements to specify default values.

Usage of Oracle DECODE function in MySQL

Oracle's DECODE function is a case statement used in Returns different values ​​under given conditions. There is no direct equivalent to the DECODE function in MySQL. However, you can use CASE expressions to achieve similar functionality.

Syntax

<code class="sql">CASE
    WHEN condition1 THEN value1
    WHEN condition2 THEN value2
    ...
    ELSE default_value
END</code>

Usage

1. Determine the conditions and return value:First, Determine the conditions for comparison and the value to return if each condition is met.
2. Use CASE expressions: Use the CASE keyword at the beginning of the expression, and then list each condition and its corresponding return value.
3. Add an ELSE statement: Add an ELSE statement to specify a default value if any condition is not met.

Example

The following example demonstrates how to use the CASE expression to implement the DECODE function in MySQL:

<code class="sql">SELECT
    CASE
        WHEN age < 18 THEN "Minor"
        WHEN age >= 18 AND age < 65 THEN "Adult"
        ELSE "Senior"
    END AS age_category
FROM people;</code>

Result:

##Minor AdultSenior

age_category

Note:

CASE expression support in MySQL Use multiple WHEN clauses as well as ELSE clauses. Therefore, you can add additional conditions as needed.

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