在MySQL的单行CASE…WHEN语句中使用多个条件

Question

Is there any way of using multiple conditions inside a single line of CASE...WHEN statement in MySQL?

For instance, I want to write a query similar to the following:

SELECT col1, col2,
CASE 
    WHEN ((condition1) AND (condition2)) THEN 1 ELSE 0
END as col3,
col4
FROM table1

How can I write a query similar to the above one appropriately in MySQL?

Answer 1

The MySQL statement you have provided looks right. Another alternative would be using IF

SELECT col1, col2, IF((condition1) AND (condition2), 1, 0), col4 from table1;

For more help you could refer to : MySQL Reference Guide

Answer 2

SELECT col1, col2,
CASE 
    WHEN (if(your_condition , 'true_Result' , 'False_result') AND if(your_condition , 'true_Result' , 'False_result')) THEN 1 ELSE 0
END as col3,
col4
FROM table1

Explanation: if(your_condition , 'true_Result' , 'False_result') If your conditions becomes true, it would pick your value set in 'true_result', if condition is false, it would pick from 'false_Result' Example: if(sum(columnname)=0 , 1 , 0) to check if a particular column contains all values as 0 or not.