[GitHub] [incubator-shardingsphere] Sy9876 opened a new issue #2725: why "select max(a) + 1 from sy" not supported even table sy is not a sharding table?

[GitBox <gi...@apache.org>]

Sy9876 opened a new issue #2725: why "select max(a) + 1 from sy" not supported even table sy is not a sharding table?
URL: https://github.com/apache/incubator-shardingsphere/issues/2725
 
 
   ## Feature Request
   
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   Please pay attention on issues you submitted, because we maybe need more details. 
   If no response **more than 7 days** and we cannot make decision by current information, we will **close it**.
   
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   ### Is your feature request related to a problem?
   When I execute the SQL on Sharding-Proxy-3.0.0, following exception occurs.
   ```
   mysql> select max(a)+1 from sy;
   ERROR 3054 (HY000): Unknown exception: Can't find index: AggregationSelectItem(type=MAX, innerExpression=(a), alias=Optional.absent(), derivedAggregationSelectItems=[], index=-1), please add alias for aggregate selections
   ```
   
   Table **sy** is not a sharding table.  In my sharding rule, table sy is not configured.
   ```
   shardingRule:
     defaultDataSourceName: ds_0
     defaultDatabaseStrategy:
       none:
     defaultTableStrategy:
       none:
     tables:
   ```
   I think sharding-proxy should use defaultTableStrategy-none rule for the SQL, send the original SQL to mysql directly.
   
   ### Describe the feature you would like.
   If a SQL statement only use none sharding tables, then send it to mysql directly.
   
   ### PS.
   Following result is directly run on mysql.
   ```
   mysql> show create table sy \G
   *************************** 1. row **************
          Table: sy
   Create Table: CREATE TABLE `sy` (
     `a` int(11) DEFAULT NULL
   ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
   1 row in set (0.10 sec)
   
   mysql> select * from sy;
   +------+
   | a    |
   +------+
   |    1 |
   |    2 |
   +------+
   2 rows in set (0.07 sec)
   
   mysql> select max(a)+1 from sy;
   +----------+
   | max(a)+1 |
   +----------+
   |        3 |
   +----------+
   1 row in set (0.09 sec)
   ```
   

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