[GitHub] [shardingsphere] strongduanmu commented on pull request #11996: optimize and or condition parse and extract logic

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

strongduanmu commented on pull request #11996:
URL: https://github.com/apache/shardingsphere/pull/11996#issuecomment-905238344


   In different database dialects, the `and` operator has a higher priority than the `or` operator, so it should be parsed according to the priority when parsing.
   
   However, the parsing engine does not distinguish the priority of `and` and `or`, which results in incorrect parsing results of the following sentences, and ultimately leads to extremely complicated logic for extracting `AndPredicate` when using the parsing results.
   
   ```sql
   SELECT * FROM t_order WHERE a = 1 AND b = 2 OR c = 3 AND d = 4 OR e = 5 AND f = 6;
   ```
   
   Current parse result:
   
   ![image](https://user-images.githubusercontent.com/10829171/130741904-16d5c1aa-1274-49c0-8896-a2b89fb29b34.png)
   
   Optimized parse result:
   
   ![image](https://user-images.githubusercontent.com/10829171/130741963-4ef1e4db-5e22-4b39-8a1b-71c099903029.png)
   
   


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