Support for the explain and do keywords in Stored Procedures

[ccxxxyy]

Fixes #35088

Changes proposed in this pull request:

---

Before committing this PR, I'm sure that I have checked the following options:

• My code follows the code of conduct of this project.
• I have self-reviewed the commit code.
• I have (or in comment I request) added corresponding labels for the pull request.
• I have passed maven check locally : ./mvnw clean install -B -T1C -Dmaven.javadoc.skip -Dmaven.jacoco.skip -e.
• I have made corresponding changes to the documentation.
• I have added corresponding unit tests for my changes.
• I have updated the Release Notes of the current development version. For more details, see Update Release Note

[Copilot]

Pull request overview

This PR adds support for the EXPLAIN and DO keywords in MySQL stored procedures by updating the ANTLR grammar and adding corresponding test cases.

• Updated the validStatement grammar rule to include doStatement and EXPLAIN as valid statements within stored procedure bodies
• Added two new test SQL cases demonstrating EXPLAIN and DO usage in stored procedures

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
parser/sql/engine/dialect/mysql/src/main/antlr4/imports/mysql/DDLStatement.g4	Extended the validStatement rule to support doStatement and EXPLAIN keywords in procedure bodies
test/it/parser/src/main/resources/sql/supported/ddl/create-procedure.xml	Added test SQL cases for procedures containing EXPLAIN and DO statements
test/it/parser/src/main/resources/case/ddl/create-procedure.xml	Added test case definitions for the new EXPLAIN and DO procedure tests

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[terrymanu]

• parser/sql/engine/dialect/mysql/src/main/antlr4/imports/mysql/DDLStatement.g4:680-687: EXPLAIN is added as a bare keyword to validStatement instead of using the explain rule. Inside BEGIN ... END, EXPLAIN SELECT ... will be parsed as two statements (EXPLAIN + SELECT), allowing an EXPLAIN with no target and losing the explain semantics. Downstream rewriting/analysis will treat it as a plain query — a behavior regression.

• parser/sql/engine/dialect/mysql/src/main/java/org/apache/shardingsphere/sql/parser/engine/mysql/visitor/statement/type/MySQLDDLStatementVisitor.java:818-844: createValidStatementSegment still only emits table/DML/SELECT nodes. Newly allowed DO/EXPLAIN would return null and be dropped, so the routine body AST will not contain DoStatement/ExplainStatement; the feature isn’t actually wired through.

• Tests are insufficient: test/it/parser/src/main/resources/sql/supported/ddl/create-procedure.xml and .../case/ddl/create-procedure.xml only add SQL cases, with no assertions on routine-body contents, so the above semantic gaps would not be caught.

  Recommendation: wire validStatement to the explain rule and include doStatement, extend the visitor to return ExplainStatement/DoStatement, and add parser assertions ensuring routine bodies contain the correct ValidStatementSegment entries.

[ccxxxyy]

@terrymanu Hi, I've already made the revisions as requested. Hope that you can review it when you have some free time.

[terrymanu]

Nice direction adding EXPLAIN/DO in stored procedures! Two small tweaks to keep behavior consistent and avoid a regression:

• MySQLDDLStatementVisitor.visitExplain (parser/sql/engine/dialect/mysql/src/main/java/org/apache/shardingsphere/sql/parser/engine/mysql/visitor/statement/type/MySQLDDLStatementVisitor.java): when ctx.tableName()!=null it currently returns visitChildren(ctx), yielding
  a SimpleTableSegment while createValidStatementSegment expects an ExplainStatement. This will throw ClassCastException and drop semantics for EXPLAIN/DESC table inside procedures. Please mirror the DAL visitor and build a MySQLDescribeStatement (including column wildcard handling) for the table-name branch.
• Coverage: add a stored-proc case with EXPLAIN/DESC table (with table name) in test/it/parser/src/main/resources/sql/supported/ddl/create-procedure.xml, and annotate the corresponding sql-statement position/type in test/it/parser/src/main/resources/case/ddl/create-procedure.xml (expect MySQLDescribeStatement), so this branch is asserted and won’t regress.

Thanks for pushing this forward—looking forward to the update!

[ccxxxyy]

@terrymanu Hi, I have made the revisions as requested. Hope that you could take a look at it when you have a moment.

[terrymanu]

• No correctness problems spotted. The patch extends the stored-procedure validStatement grammar to accept DO and EXPLAIN (parser/sql/engine/dialect/mysql/src/main/antlr4/imports/mysql/DDLStatement.g4:683) and teaches the DDL visitor to build DoStatement/
  ExplainStatement/MySQLDescribeStatement nodes for them (parser/sql/engine/dialect/mysql/src/main/java/org/apache/shardingsphere/sql/parser/engine/mysql/visitor/statement/type/MySQLDDLStatementVisitor.java:857,874), aligning stored-procedure parsing with standalone statement handling.
• New parser IT cases cover EXPLAIN SELECT, DO SLEEP(...), and table DESCRIBE/EXPLAIN inside procedures (test/it/parser/src/main/resources/sql/supported/ddl/create-procedure.xml:62, test/it/parser/src/main/resources/case/ddl/create-procedure.xml:143), so the added paths are exercised.
• Looks safe to merge; it addresses the root cause (missing DO/EXPLAIN in routine-body grammar) rather than papering over it.