row1：

abc@sev.com.cn;

123@seeco.com;

ef@sevloal.com;

ddd@seobal.com

row2：

AAAA@se23vloal.com;

BBBB@seo234bal.com

把同一個Column的字符串，通過分隔符分割后逐行插入數據庫。

substring_index 定位是位置的左边，或者右边。而不能准确定位字符，需要做判断来返回正确的结果。

SELECT * FROM temp_biz_email
WHERE email_to='ech.com.cn'INSERT temp_biz_email2(cust_no,email,carbon) 
SELECT cust_no,
SUBSTRING_INDEX(email_to,';',1) 
AS to1,1 FROM `temp_biz_email`INSERT temp_biz_email2(cust_no,email,carbon) 
SELECT * from (
SELECT cust_no,
IF (SUBSTRING_INDEX(email_to,';',1)= email_to,NULL,
SUBSTRING_INDEX(
SUBSTRING_INDEX(email_to,';',2),';',-1)) 
AS email_to,1
FROM `temp_biz_email`
) AS tab WHERE tab.email_to !=''

对于第一个匹配的位置，可能会出现空的情况，例如 ；；；；；，去除null

INSERT temp_biz_email2(cust_no,email,carbon) 
SELECT * from (
SELECT cust_no,SUBSTRING_INDEX(email_cc,';',1) 
AS email_cc,1 FROM `temp_biz_email`
) AS tab WHERE tab.email_cc !='' AND email_cc not LIKE '%@eaddeek.com%'