FlyingZC opened a new issue, #29156:
URL: https://github.com/apache/shardingsphere/issues/29156

   # Background
   Hi community.
   This issue is for #29149.
   
   The ShardingSphere SQL parser engine helps users to parse SQL to create the 
AST (Abstract Syntax Tree) and visit the AST to get SQLStatement (Java Object). 
Currently, we are planning to enhance the support for `SQL Server` SQL parsing 
in ShardingSphere.
   
   More details:
   
https://shardingsphere.apache.org/document/current/en/reference/sharding/parse/
   
   # Task
   This issue is to support more `SQL Server` sql parsing, as follows:
   ```sql
   SELECT DISTINCT user.FirstName, user.LastName
   INTO ms_user
   FROM user INNER JOIN (
       SELECT * FROM ClickStream WHERE cs.url = 'www.microsoft.com'
       ) AS ms
   ON user.user_ip = ms.user_ip
   ```
   
[link](https://learn.microsoft.com/zh-cn/sql/t-sql/statements/create-external-table-transact-sql?view=sql-server-ver16)
   
   ```sql
   SELECT 
       req.session_id
       , req.total_elapsed_time AS duration_ms
       , req.cpu_time AS cpu_time_ms
       , req.total_elapsed_time - req.cpu_time AS wait_time
       , req.logical_reads
       , SUBSTRING (REPLACE (REPLACE (SUBSTRING (ST.text, 
(req.statement_start_offset/2) + 1, 
          ((CASE statement_end_offset
              WHEN -1
              THEN DATALENGTH(ST.text)  
              ELSE req.statement_end_offset
            END - req.statement_start_offset)/2) + 1) , CHAR(10), ' '), 
CHAR(13), ' '), 
         1, 512)  AS statement_text  
   FROM sys.dm_exec_requests AS req
       CROSS APPLY sys.dm_exec_sql_text(req.sql_handle) AS ST
   ORDER BY total_elapsed_time DESC
   ```
   
[link](https://learn.microsoft.com/zh-cn/troubleshoot/sql/database-engine/performance/troubleshoot-slow-running-queries)
   
   ```sql
   SELECT t.text,
        (qs.total_elapsed_time/1000) / qs.execution_count AS avg_elapsed_time,
        (qs.total_worker_time/1000) / qs.execution_count AS avg_cpu_time,
        ((qs.total_elapsed_time/1000) / qs.execution_count ) - 
((qs.total_worker_time/1000) / qs.execution_count) AS avg_wait_time,
        qs.total_logical_reads / qs.execution_count AS avg_logical_reads,
        qs.total_logical_writes / qs.execution_count AS avg_writes,
        (qs.total_elapsed_time/1000) AS cumulative_elapsed_time_all_executions
   FROM sys.dm_exec_query_stats qs
        CROSS apply sys.Dm_exec_sql_text (sql_handle) t
   WHERE t.text like '<Your Query>%'
   -- Replace <Your Query> with your query or the beginning part of your query. 
The special chars like '[','_','%','^' in the query should be escaped.
   ORDER BY (qs.total_elapsed_time / qs.execution_count) DESC
   ```
   
[link](https://learn.microsoft.com/zh-cn/troubleshoot/sql/database-engine/performance/troubleshoot-slow-running-queries)
   
   ```sql
   SELECT t.text,
            qs.total_elapsed_time / qs.execution_count
            AS avg_elapsed_time,
            qs.total_worker_time / qs.execution_count
            AS avg_cpu_time,
            (qs.total_elapsed_time - qs.total_worker_time) / qs.execution_count
            AS avg_wait_time,
            qs.total_logical_reads / qs.execution_count
            AS avg_logical_reads,
            qs.total_logical_writes / qs.execution_count
            AS avg_writes,
            qs.total_elapsed_time
            AS cumulative_elapsed_time
   FROM sys.dm_exec_query_stats qs
            CROSS apply sys.Dm_exec_sql_text (sql_handle) t
   WHERE (qs.total_elapsed_time - qs.total_worker_time) / qs.total_elapsed_time
            > 0.2
   ORDER BY qs.total_elapsed_time / qs.execution_count DESC
   ```
   
[link](https://learn.microsoft.com/zh-cn/troubleshoot/sql/database-engine/performance/troubleshoot-slow-running-queries)
   
   ```sql
   SELECT 'DECLARE @serverName NVARCHAR(512) = N''' + value + ''''
   FROM sys.dm_hadr_fabric_config_parameters
   WHERE parameter_name = 'DnsRecordName'
   
   UNION
   
   SELECT 'DECLARE @node NVARCHAR(512) = N''' + NodeName + '.' + Cluster + ''''
   FROM (
       SELECT SUBSTRING(replica_address, 0, CHARINDEX('\', replica_address)) AS 
NodeName,
           RIGHT(service_name, CHARINDEX('/', REVERSE(service_name)) - 1) 
AppName,
           JoinCol = 1
       FROM sys.dm_hadr_fabric_partitions fp
       INNER JOIN sys.dm_hadr_fabric_replicas fr
           ON fp.partition_id = fr.partition_id
       INNER JOIN sys.dm_hadr_fabric_nodes fn
           ON fr.node_name = fn.node_name
       WHERE service_name LIKE '%ManagedServer%'
           AND replica_role = 2
   ) t1
   LEFT JOIN (
       SELECT value AS Cluster,
           JoinCol = 1
       FROM sys.dm_hadr_fabric_config_parameters
       WHERE parameter_name = 'ClusterName'
       ) t2
       ON (t1.JoinCol = t2.JoinCol)
   INNER JOIN (
       SELECT [value] AS AppName
       FROM sys.dm_hadr_fabric_config_parameters
       WHERE section_name = 'SQL'
           AND parameter_name = 'InstanceName'
       ) t3
       ON (t1.AppName = t3.AppName)
   
   UNION
   
   SELECT 'DECLARE @port NVARCHAR(512) = N''' + value + ''''
   FROM sys.dm_hadr_fabric_config_parameters
   WHERE parameter_name = 'HadrPort'
   ```
   
[link](https://learn.microsoft.com/zh-cn/azure/azure-sql/managed-instance/managed-instance-link-preparation?view=azuresql)
   
   # Process
   1. First confirm that this is a correct `SQL Server` sql syntax, if not 
please leave a message under the issue and ignore it;
   2. Compare SQL definitions in Official SQL Doc and ShardingSphere SQL Doc;
   3. If there is any difference in ShardingSphere SQL Doc, please correct them 
by referring to the Official SQL Doc;
   4. Run mvn install the current_file_module;
   5. Check whether there are any exceptions. If indeed, please fix them. 
(Especially xxxVisitor.class);
   6. Add new corresponding SQL case in SQL Cases and expected parsed result in 
Expected Statement XML;
   7. Run SQLParserParameterizedTest to make sure no exceptions.
   
   # Relevant Skills
   1. Master JAVA language
   2. Have a basic understanding of Antlr `g4` file
   3. Be familiar with `SQL Server` SQLs


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