substring_index(input,split,index)：input為要截bai取du的字符场靴，split為分隔符，Index為要截取第index個(gè)分隔符左（index為正）或右(index為負(fù)zhi)的字符串户辞。
舉例dao：
'Provider="RiskManagement" finalScore="65" RGID="100397278"' //獲取finalScore的值
1、獲取finalScore右邊的字符
select substring_index('Provider="RiskManagement" finalScore="65" RGID="100397278"','finalScore="',-1);
2渴频、再獲取" RGID="左邊的字符
select substring_index(substring_index('Provider="RiskManagement" finalScore="65" RGID="100397278"','finalScore="',-1),'" RGID="',1);
