我试图通过存储过程取出一个字段,我使用了以下查询.我的目标是获取多行,但只有当存在一行时才能成功执行结果.否则它会返回错误,如下所述.

MYSQL查询

delimiter ;;
    drop procedure if exists Sample1;;
    CREATE PROCEDURE Sample1(IN lft1 INT,IN rgt1 INT,OUT emp1 VARCHAR(20))
    BEGIN
    SELECT  p.emp into emp1 FROM personnell p WHERE p.lft>lft1  and p.rgt < rgt1 LIMIT 10;
    END;;
    call Sample1(1,10,@emp);;
    select @emp;

错误信息

MysqL said: Documentation
#1172 - Result consisted of more than one row 

注意

-----
Sample1--- procedure name;
emp -----selected field from table personnell
lft -----use to check the condition,it is also one of the field of table personnell
personnell------table name