improved oracle sql parser support fetch clause. issue #1448

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelectQueryBlock.java

@@ -37,6 +37,7 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
     protected boolean                   forUpdate     = false;
     protected boolean                   noWait        = false;
     protected SQLExpr                   waitTime;
+    protected SQLExpr                   first;
 
     public SQLSelectQueryBlock(){
 
@@ -142,9 +143,24 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
     }
     
     public void setWaitTime(SQLExpr waitTime) {
+        if (waitTime != null) {
+            waitTime.setParent(this);
+        }
         this.waitTime = waitTime;
     }
 
+
+    public SQLExpr getFirst() {
+        return first;
+    }
+
+    public void setFirst(SQLExpr first) {
+        if (first != null) {
+            first.setParent(this);
+        }
+        this.first = first;
+    }
+
 	@Override
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {

src/main/java/com/alibaba/druid/sql/dialect/db2/ast/stmt/DB2SelectQueryBlock.java

@@ -23,7 +23,7 @@ import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Object {
 
-    private SQLExpr   first;
+
 
     private Isolation isolation;
 
@@ -31,14 +31,6 @@ public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Objec
 
     private SQLExpr   optimizeFor;
 
-    public SQLExpr getFirst() {
-        return first;
-    }
-
-    public void setFirst(SQLExpr first) {
-        this.first = first;
-    }
-
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor instanceof DB2ASTVisitor) {

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2OutputVisitor.java

@@ -38,27 +38,6 @@ public class DB2OutputVisitor extends SQLASTOutputVisitor implements DB2ASTVisit
     public boolean visit(DB2SelectQueryBlock x) {
         this.visit((SQLSelectQueryBlock) x);
 
-        if (x.getFirst() != null) {
-
-            //order by 语句必须在FETCH FIRST ROWS ONLY之前
-            SQLObject parent= x.getParent();
-            if(parent instanceof SQLSelect)
-            {
-                SQLOrderBy orderBy= ((SQLSelect) parent).getOrderBy();
-                if (orderBy!=null&&orderBy.getItems().size() > 0) {
-                    println();
-                    print0(ucase ? "ORDER BY " : "order by ");
-                    printAndAccept(orderBy.getItems(), ", ");
-                    ((SQLSelect) parent).setOrderBy(null);
-                }
-            }
-            println();
-            print0(ucase ? "FETCH FIRST " : "fetch first ");
-            x.getFirst().accept(this);
-            print0(ucase ? " ROWS ONLY" : " rows only");
-
-
-        }
         if (x.isForReadOnly()) {
             println();
             print0(ucase ? "FOR READ ONLY" : "for read only");

src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleLexer.java

@@ -109,6 +109,8 @@ public class OracleLexer extends Lexer {
         map.put("PURGE", Token.PURGE);
         map.put("INITIALLY", Token.INITIALLY);
 
+        map.put("FETCH", Token.FETCH);
+
         DEFAULT_ORACLE_KEYWORDS = new Keywords(map);
     }
 

src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleSelectParser.java

@@ -276,6 +276,8 @@ public class OracleSelectParser extends SQLSelectParser {
 
         parseModelClause(queryBlock);
 
+        parseFetchClause(queryBlock);
+
         return queryRest(queryBlock);
     }
 

src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleOutputVisitor.java

@@ -17,12 +17,7 @@ package com.alibaba.druid.sql.dialect.oracle.visitor;
 
 import java.util.List;
 
-import com.alibaba.druid.sql.ast.SQLExpr;
-import com.alibaba.druid.sql.ast.SQLHint;
-import com.alibaba.druid.sql.ast.SQLObject;
-import com.alibaba.druid.sql.ast.SQLParameter;
-import com.alibaba.druid.sql.ast.SQLSetQuantifier;
-import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.ast.*;
 import com.alibaba.druid.sql.ast.expr.SQLAllColumnExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
@@ -572,6 +567,8 @@ public class OracleOutputVisitor extends SQLASTOutputVisitor implements OracleAS
             x.getModelClause().accept(this);
         }
 
+        printFetchFirst(x);
+
         return false;
     }
 

src/main/java/com/alibaba/druid/sql/parser/SQLSelectParser.java

@@ -540,4 +540,25 @@ public class SQLSelectParser extends SQLParser {
         }
     }
 
+    public void parseFetchClause(SQLSelectQueryBlock queryBlock) {
+        if (lexer.token() == Token.FETCH) {
+            lexer.nextToken();
+            if (lexer.token() == Token.FIRST) {
+                lexer.nextToken();
+            } else {
+                acceptIdentifier("FIRST");
+            }
+            SQLExpr first = this.exprParser.primary();
+            queryBlock.setFirst(first);
+            if (identifierEquals("ROW") || identifierEquals("ROWS")) {
+                lexer.nextToken();
+            }
+
+            if (lexer.token() == Token.ONLY) {
+                lexer.nextToken();
+            } else {
+                acceptIdentifier("ONLY");
+            }
+        }
+    }
 }

src/main/java/com/alibaba/druid/sql/visitor/SQLASTOutputVisitor.java

@@ -787,9 +787,31 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
             x.getOrderBy().accept(this);
         }
 
+        printFetchFirst(x);
+
         return false;
     }
 
+    protected void printFetchFirst(SQLSelectQueryBlock x) {
+        if (x.getFirst() != null) {
+            //order by 语句必须在FETCH FIRST ROWS ONLY之前
+            SQLObject parent= x.getParent();
+            if(parent instanceof SQLSelect) {
+                SQLOrderBy orderBy = ((SQLSelect) parent).getOrderBy();
+                if (orderBy!=null&&orderBy.getItems().size() > 0) {
+                    println();
+                    print0(ucase ? "ORDER BY " : "order by ");
+                    printAndAccept(orderBy.getItems(), ", ");
+                    ((SQLSelect) parent).setOrderBy(null);
+                }
+            }
+            println();
+            print0(ucase ? "FETCH FIRST " : "fetch first ");
+            x.getFirst().accept(this);
+            print0(ucase ? " ROWS ONLY" : " rows only");
+        }
+    }
+
     public boolean visit(SQLSelectItem x) {
         if (x.isConnectByRoot()) {
             print0(ucase ? "CONNECT_BY_ROOT " : "connect_by_root ");