返回類型爲字符串,使用NVL()函數
SELECT nvl(t2.codetypename,‘沒找到’) aa
/* INTO szchannelname*/
FROM sl_codetypedef t2
WHERE t2.codetype = ‘CHANNEL’ AND t2.codetypeno = ‘98’;
這樣的話,無法返回結果,如圖:
將引用改爲:nvl(select from)外面
SELECT nvl( (SELECT t2.codetypename
FROM sl_codetypedef t2
WHERE t2.codetype = ‘CHANNEL’ AND t2.codetypeno = ‘98’ and rownum=1),‘沒找到’) FROM DUAL;