[GitHub] [shardingsphere] tristaZero commented on issue #8982: show tables like xxx% can not return correct result

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tristaZero commented on issue #8982:
URL: https://github.com/apache/shardingsphere/issues/8982#issuecomment-835809084


   Hi @MingxingLAI ,
   Thanks for your attention here, sorry for my late coming.
   Let consider this issue with the following scenario,
   
   Suppose here are some tables,
   ```
   t_order (a sharding logic table, including t_order_0, t_order_1)
   t_order_item (a sharding logic table, including t_order_item_0, t_order_item_1)
   t_order_number(a single table)
   t_order_metadata(a broadcast table, each instance has this table)
   t_item_order(a single table)
   ```
   Now, how to filter and return all the `logic tables` to users by `show tables like '%t_order%"?
   
   Firstly,  we need to put maybe two (?) `flags`(`%`) in 'showStatement` to mark it for usage later on.
   Secondly, `show tables like '%t_order%" will be sent to all the DB instances to get all the `actual` tables.
   Thirdly, we need to deal with these results in  `LogicTablesMergedResult`, including,
   - Merge some of the actual tables into `sharding tables` by sharding rules
   - Filter all the target `logic tables` (sharding tables, single tables, broadcast tables) with the two of  `%` marks in  `showStatement` and sharding rules
   Last but not least, do not forget unit tests to verify your modification.
   


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