Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='

存储过程代码： 
1 BEGIN
DECLARE studentNum_1 VARCHAR(50) CHARACTER SET utf8;
DECLARE testId_1 VARCHAR(100) CHARACTER SET utf8;
DECLARE testName_1 VARCHAR(200) CHARACTER SET utf8;
DECLARE testScore_1 DOUBLE;

DECLARE num int DEFAULT 0;

DECLARE test_cursor CURSOR FOR SELECT USERID,PUBLISHEDASSESSMENTID,TITLE,FINALSCORE FROM gradinginfo WHERE gradinginfo.SITEID=siteId /*COLLATE utf8_unicode_ci*/;

DECLARE CONTINUE HANDLER for not found SET num=1;

OPEN test_cursor;
FETCH test_cursor INTO studentNum_1,testId_1,testName_1,testScore_1;

WHILE num<>1 DO
IF testScore_1 IS NULL THEN
SET testScore_1=0;
END IF;


INSERT INTO e_studenttest(siteId,studentNum,testId,testName,testScore) VALUEs(siteId,studentNum_1,testId_1,testName_1,testScore_1);
FETCH test_cursor INTO  studentNum_1,testId_1,testName_1,testScore_1;
end WHILE;

CLOSE test_cursor;
SELECT 1;
END

 表gradinginf的结构设计：

错误原因：在存储过程中，使用了此语句DECLARE test_cursor CURSOR FOR SELECT USERID,PUBLISHEDASSESSMENTID,TITLE,FINALSCORE FROM gradinginfo WHERE gradinginfo.SITEID=siteId

存储过程的参数varchar的排序规则默认为utf8_general_ci，而在表gradinginfo中的字段siteId的排序规则是utf_unicode_ci,两者混用便会报错。

解决办法：

1）：在参数时设置为utf8_unicode_ci

Create procedure error(in siteId varchar(100) COLLATE utf8_unicode_ci)----但此种方法在我的mysq中会提示：该mysql版本不支持

 2）：把表gradinginfo中的字段siteId的排序规则由utf_unicode_ci更改为utf8_general_ci

3）：在where语句中加上COLLATE utf8_unicode_ci

WHERE gradinginfo.SITEID=siteId COLLATE utf8_unicode_ci