南大通用GBase 8a数据库在出现分隔符时，应用string_to_array函数拆分字符串，将拆分后的数据形成文本数组。
语法：
string_to_array(str,delimiter[,null_string])
str：待分割的字符串，如为'',则返回''
delimiter：分割字符串，如为'',则返回整个待分割的串为一个元素；如为null，则待分割的串中每个字符为一个元素
null_string：设定空串的字符串，可选。返回的数组元素中如与该参数匹配则替换为NULL。
示例：
gbase> select string_to_array('xx~^yy^zz','^~');
+---------------------------------------+
| string_to_array('xx~^yy^zz','^~') |
+---------------------------------------+
| ['xx','yy','zz'] |
+---------------------------------------+
1 row in set (Elapsed: 00:00:00.00)
gbase> select string_to_array('xx~^aa^zz','^~','aa');
+--------------------------------------------+
| string_to_array('xx~^aa^zz','^~','aa') |
+--------------------------------------------+
| ['xx',NULL,'zz'] |
+--------------------------------------------+
1 row in set (Elapsed: 00:00:00.00)
gbase> select string_to_array('xx~^yy^~zz','');
+------------------------------------+
| string_to_array('xx~^yy^~zz','') |
+------------------------------------+
| ['xx~^yy^~zz'] |
+------------------------------------+
1 row in set (Elapsed: 00:00:00.01)
