Improve the definition of select (#7938)

* Improve the definition of select

* fix

shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/antlr4/imports/mysql/BaseRule.g4

@@ -648,3 +648,7 @@ cursorName
 conditionName
     : identifier
     ;
+
+unionOption
+    : ALL | DISTINCT
+    ;

shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/antlr4/imports/mysql/DALStatement.g4

@@ -381,7 +381,7 @@ explainType
     ;
 
 explainableStatement
-    : select | tableStatement | delete | insert | replace | update
+    : select | delete | insert | replace | update
     ;
 
 formatName

shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/antlr4/imports/mysql/DMLStatement.g4

@@ -105,15 +105,46 @@ singleTableClause
     ;
 
 multipleTablesClause
-    : multipleTableNames FROM tableReferences | FROM multipleTableNames USING tableReferences
+    : tableAliasRefList FROM tableReferences | FROM tableAliasRefList USING tableReferences
     ;
 
 multipleTableNames
     : tableName DOT_ASTERISK_? (COMMA_ tableName DOT_ASTERISK_?)*
     ;
 
-select 
-    : withClause? unionClause
+select
+    : queryExpression lockClauseList?
+    | queryExpressionParens
+    | selectWithInto
+    ;
+
+selectWithInto
+    : LP_ selectWithInto RP_
+    | queryExpression selectIntoExpression lockClauseList?
+    | queryExpression lockClauseList selectIntoExpression
+    ;
+
+queryExpression
+    : withClause? (queryExpressionBody | queryExpressionParens) orderByClause? limitClause?
+    ;
+
+queryExpressionBody
+    : queryPrimary
+    | queryExpressionParens UNION unionOption? (queryPrimary | queryExpressionParens)
+    ;
+
+queryExpressionParens
+    : LP_ (queryExpressionParens | queryExpression lockClauseList?) RP_
+    ;
+
+queryPrimary
+    : querySpecification
+    | tableValueConstructor
+    | explicitTable
+    ;
+
+querySpecification
+    : SELECT selectSpecification* projections selectIntoExpression? fromClause? whereClause? groupByClause? havingClause? windowClause?
     ;
 
 call
@@ -177,12 +208,12 @@ loadXmlStatement
       (setAssignmentsClause)?
     ;
 
-tableStatement
-    : TABLE tableName (ORDER BY columnName)? (LIMIT NUMBER_ (OFFSET NUMBER_)?)?
+explicitTable
+    : TABLE tableName
     ;
 
-valuesStatement
-    : VALUES rowConstructorList (ORDER BY columnDesignator)? (LIMIT BY NUMBER_)?
+tableValueConstructor
+    : VALUES rowConstructorList
     ;
 
 columnDesignator
@@ -201,14 +232,6 @@ cteClause
     : ignoredIdentifier columnNames? AS subquery
     ;
 
-unionClause
-    : selectClause (UNION (ALL | DISTINCT)? selectClause)*
-    ;
-
-selectClause
-    : LP_? SELECT selectSpecification* projections selectIntoExpression? fromClause? whereClause? groupByClause? havingClause? windowClause? orderByClause? limitClause? selectIntoExpression? lockClause? RP_?
-    ;
-
 selectSpecification
     : duplicateSpecification | HIGH_PRIORITY | STRAIGHT_JOIN | SQL_SMALL_RESULT | SQL_BIG_RESULT | SQL_BUFFER_RESULT | (SQL_CACHE | SQL_NO_CACHE) | SQL_CALC_FOUND_ROWS
     ;
@@ -308,7 +331,7 @@ windowItem
     ;
 
 subquery
-    : LP_ unionClause RP_
+    : queryExpressionParens
     ;
 
 selectLinesInto
@@ -325,5 +348,31 @@ selectIntoExpression
     ;
 
 lockClause
-    : FOR UPDATE | LOCK IN SHARE MODE
+    : FOR lockStrength lockedRowAction?
+    | FOR lockStrength
+    | LOCK IN SHARE MODE
+    ;
+
+lockClauseList
+    : lockClause+
+    ;
+
+lockStrength
+    : UPDATE | SHARE
+    ;
+
+lockedRowAction
+    : SKIP_SYMBOL LOCKED | NOWAIT
+    ;
+
+tableLockingList
+    : OF tableAliasRefList
+    ;
+
+tableIdentOptWild
+    : tableName DOT_ASTERISK_?
+    ;
+
+tableAliasRefList
+    : tableIdentOptWild+
     ;

shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/antlr4/imports/mysql/MySQLKeyword.g4

@@ -2259,9 +2259,9 @@ SIMPLE
     : S I M P L E
     ;
 
-//SKIP
-//    : S K I P
-//    ;
+SKIP_SYMBOL
+    : S K I P
+    ;
 
 SLAVE
     : S L A V E

shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/java/org/apache/shardingsphere/sql/parser/mysql/visitor/statement/impl/MySQLStatementSQLVisitor.java

@@ -498,9 +498,72 @@ public abstract class MySQLStatementSQLVisitor extends MySQLStatementBaseVisitor
     
     @Override
     public ASTNode visitSubquery(final SubqueryContext ctx) {
-        return visit(ctx.unionClause());
+        return visit(ctx.queryExpressionParens());
     }
-    
+
+    @Override
+    public ASTNode visitQueryExpressionParens(final MySQLStatementParser.QueryExpressionParensContext ctx) {
+        if (null != ctx.queryExpressionParens()) {
+            return visit(ctx.queryExpressionParens());
+        }
+        MySQLSelectStatement result = (MySQLSelectStatement) visit(ctx.queryExpression());
+        if (null != ctx.lockClauseList()) {
+            result.setLock((LockSegment) visit(ctx.lockClauseList()));
+        }
+        result.setParameterCount(getCurrentParameterIndex());
+        return result;
+    }
+
+    @Override
+    public ASTNode visitLockClauseList(final MySQLStatementParser.LockClauseListContext ctx) {
+        return new LockSegment(ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex());
+    }
+
+    @Override
+    public ASTNode visitQueryExpression(final MySQLStatementParser.QueryExpressionContext ctx) {
+        MySQLSelectStatement result;
+        if (null != ctx.queryExpressionBody()) {
+            result = (MySQLSelectStatement) visit(ctx.queryExpressionBody());
+        } else {
+            result = (MySQLSelectStatement) visit(ctx.queryExpressionParens());
+        }
+        if (null != ctx.orderByClause()) {
+            result.setOrderBy((OrderBySegment) visit(ctx.orderByClause()));
+        }
+        if (null != ctx.limitClause()) {
+            result.setLimit((LimitSegment) visit(ctx.limitClause()));
+        }
+        return result;
+    }
+
+    @Override
+    public ASTNode visitQueryExpressionBody(final MySQLStatementParser.QueryExpressionBodyContext ctx) {
+        if (1 == ctx.getChildCount() && ctx.getChild(0) instanceof MySQLStatementParser.QueryPrimaryContext) {
+            return visit(ctx.queryPrimary());
+        }
+        throw new IllegalStateException("union select is not supported yet.");
+    }
+
+    @Override
+    public ASTNode visitQuerySpecification(final MySQLStatementParser.QuerySpecificationContext ctx) {
+        MySQLSelectStatement result = new MySQLSelectStatement();
+        result.setProjections((ProjectionsSegment) visit(ctx.projections()));
+        if (null != ctx.selectSpecification()) {
+            result.getProjections().setDistinctRow(isDistinct(ctx));
+        }
+        if (null != ctx.fromClause()) {
+            TableSegment tableSource = (TableSegment) visit(ctx.fromClause().tableReferences());
+            result.setFrom(tableSource);
+        }
+        if (null != ctx.whereClause()) {
+            result.setWhere((WhereSegment) visit(ctx.whereClause()));
+        }
+        if (null != ctx.groupByClause()) {
+            result.setGroupBy((GroupBySegment) visit(ctx.groupByClause()));
+        }
+        return result;
+    }
+
     @Override
     public final ASTNode visitIntervalExpression(final IntervalExpressionContext ctx) {
         calculateParameterCount(Collections.singleton(ctx.intervalValue().expr()));
@@ -950,14 +1013,14 @@ public abstract class MySQLStatementSQLVisitor extends MySQLStatementBaseVisitor
         DeleteMultiTableSegment result = new DeleteMultiTableSegment();
         TableSegment relateTableSource = (TableSegment) visit(ctx.tableReferences());
         result.setRelationTable(relateTableSource);
-        result.setActualDeleteTables(generateTablesFromTableMultipleTableNames(ctx.multipleTableNames()));
+        result.setActualDeleteTables(generateTablesFromTableMultipleTableNames(ctx.tableAliasRefList()));
         return result;
     }
     
-    private List<SimpleTableSegment> generateTablesFromTableMultipleTableNames(final MySQLStatementParser.MultipleTableNamesContext ctx) {
+    private List<SimpleTableSegment> generateTablesFromTableMultipleTableNames(final MySQLStatementParser.TableAliasRefListContext ctx) {
         List<SimpleTableSegment> result = new LinkedList<>();
-        for (TableNameContext each : ctx.tableName()) {
-            result.add((SimpleTableSegment) visit(each));
+        for (MySQLStatementParser.TableIdentOptWildContext each : ctx.tableIdentOptWild()) {
+            result.add((SimpleTableSegment) visit(each.tableName()));
         }
         return result;
     }
@@ -965,47 +1028,20 @@ public abstract class MySQLStatementSQLVisitor extends MySQLStatementBaseVisitor
     @Override
     public ASTNode visitSelect(final MySQLStatementParser.SelectContext ctx) {
         // TODO :Unsupported for withClause.
-        MySQLSelectStatement result = (MySQLSelectStatement) visit(ctx.unionClause());
-        result.setParameterCount(getCurrentParameterIndex());
-        return result;
-    }
-    
-    @Override
-    public ASTNode visitUnionClause(final MySQLStatementParser.UnionClauseContext ctx) {
-        // TODO :Unsupported for union SQL.
-        return visit(ctx.selectClause(0));
-    }
-    
-    @Override
-    public ASTNode visitSelectClause(final MySQLStatementParser.SelectClauseContext ctx) {
-        MySQLSelectStatement result = new MySQLSelectStatement();
-        result.setProjections((ProjectionsSegment) visit(ctx.projections()));
-        if (null != ctx.selectSpecification()) {
-            result.getProjections().setDistinctRow(isDistinct(ctx));
-        }
-        if (null != ctx.fromClause()) {
-            TableSegment tableSource = (TableSegment) visit(ctx.fromClause().tableReferences());
-            result.setFrom(tableSource);
-        }
-        if (null != ctx.whereClause()) {
-            result.setWhere((WhereSegment) visit(ctx.whereClause()));
-        }
-        if (null != ctx.groupByClause()) {
-            result.setGroupBy((GroupBySegment) visit(ctx.groupByClause()));
-        }
-        if (null != ctx.orderByClause()) {
-            result.setOrderBy((OrderBySegment) visit(ctx.orderByClause()));
-        }
-        if (null != ctx.limitClause()) {
-            result.setLimit((LimitSegment) visit(ctx.limitClause()));
-        }
-        if (null != ctx.lockClause()) {
-            result.setLock((LockSegment) visit(ctx.lockClause()));
+        MySQLSelectStatement result;
+        if (null != ctx.queryExpression()) {
+            result = (MySQLSelectStatement) visit(ctx.queryExpression());
+            if (null != ctx.lockClauseList()) {
+                result.setLock((LockSegment) visit(ctx.lockClauseList()));
+            }
+        } else {
+            result = (MySQLSelectStatement) visit(ctx.getChild(0));
         }
+        result.setParameterCount(getCurrentParameterIndex());
         return result;
     }
     
-    private boolean isDistinct(final MySQLStatementParser.SelectClauseContext ctx) {
+    private boolean isDistinct(final MySQLStatementParser.QuerySpecificationContext ctx) {
         for (MySQLStatementParser.SelectSpecificationContext each : ctx.selectSpecification()) {
             if (((BooleanLiteralValue) visit(each)).getValue()) {
                 return true;
@@ -1258,9 +1294,4 @@ public abstract class MySQLStatementSQLVisitor extends MySQLStatementBaseVisitor
         }
         return new ParameterMarkerLimitValueSegment(ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex(), ((ParameterMarkerValue) visit(ctx.parameterMarker())).getValue());
     }
-    
-    @Override
-    public ASTNode visitLockClause(final MySQLStatementParser.LockClauseContext ctx) {
-        return new LockSegment(ctx.getStart().getStartIndex(), ctx.getStop().getStopIndex());
-    }
 }