SELECT
    CASE 3 
        WHEN 1 THEN    ‘one‘ 
        WHEN 2 THEN    ‘two‘ 
    ELSE ‘more‘ END;

SELECT
    CASE WHEN 1 > 0 THEN ‘true‘ ELSE ‘false‘ END AS ‘one‘,
    CASE WHEN 0 > 0 THEN ‘true‘ ELSE ‘false‘ END AS ‘two‘;

SELECT 
    CASE BINARY ‘BB‘
        WHEN ‘a‘ THEN 1 
        WHEN ‘bb
 
‘ THEN 2 
    END; 

SELECT 
    CASE ‘B‘
        WHEN ‘a‘ THEN 1 
        WHEN ‘b‘ THEN 2 
    END; 

SELECT IF(1>2,2,3);

select STRCMP(‘text2‘, ‘text‘); 

這裏要使用變量來保存數據，直接使用@變量

SET @cq:=(SELECT A.id FROM emis.view1 A WHERE id = 6);
SELECT @cq AS ‘變量聲明賦值的方法‘;

SET @c=(SELECT A.printer_addr FROM emis.view1 A WHERE id = @cq);
SELECT @c AS 
 
‘變量聲明賦值的方法 @cq 查找‘;


註意上面兩種賦值符號，使用set時可以用“=”或“：=”，但是使用select時必須用“：=賦值” 
SELECT @bb:=id FROM emis.view1 A WHERE id = @cq;

SELECT @bb;

Mysql 變量&分支