南大通用GBase 8a数据库to_number关联报错问题处理方法

问题现象

to_number和decimal列关联时报错，报错内容如下：

ERROR 1149 (42000): (GBA-02SC-1001) Data types of equivalence join relation ((to_number(`a`.`a`) = `b`.`a`)) are not supported , data types: left is DOUBLE, right is DECIMAL(22,0)

具体复现过程：

gbase> create table t_to_number_dec(a decimal(22,0));
Query OK, 0 rows affected (Elapsed: 00:00:02.04)
gbase> create table t_to_number_varchar(a varchar(10));
Query OK, 0 rows affected (Elapsed: 00:00:00.12)
gbase> insert into t_to_number_dec values (111111);
Query OK, 1 row affected (Elapsed: 00:00:00.39)
gbase> insert into t_to_number_varchar values ('111111');
Query OK, 1 row affected (Elapsed: 00:00:00.35)
gbase> select * from t_to_number_varchar a join t_to_number_dec b on to_number(a.a) = b.a;
ERROR 1149 (42000): (GBA-02SC-1001) Data types of equivalence join relation ((to_number(`a`.`a`) = `b`.`a`)) are not supported , data types: left is DOUBLE, right is DECIMAL(22,0)

解决方案：

修改gbase_to_number_str2dec为1，修改后执行情况如下：

gbase> set gbase_to_number_str2dec = 1;
Query OK, 0 rows affected (Elapsed: 00:00:00.00)
gbase> select * from t_to_number_varchar a join t_to_number_dec b on to_number(a.a) = b.a;
+--------+--------+
| a      | a      |
+--------+--------+
| 111111 | 111111 |
+--------+--------+
1 row in set (Elapsed: 00:00:00.12)

附：gbase_to_number_str2dec参数含义：

to_number函数在处理字符串时，转换后的类型时，参数值为0时转换成double类型，参数值为1时，转换成decimal(65,30)类型。

默认值:'OFF，0
最小值:'OFF’，0
最大值:ON’，1
级别: global、session