improved sql parser for sqlserver, support offset fetch clause

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/SQLServerSelect.java

@@ -18,6 +18,7 @@ package com.alibaba.druid.sql.dialect.sqlserver.ast;
 import java.util.ArrayList;
 import java.util.List;
 
+import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelect;
 import com.alibaba.druid.sql.dialect.sqlserver.visitor.SQLServerASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -27,6 +28,9 @@ public class SQLServerSelect extends SQLSelect implements SQLServerObject {
     private boolean      forBrowse;
     private List<String> forXmlOptions = new ArrayList<String>(4);
 
+    private SQLExpr      rowCount;
+    private SQLExpr      offset;
+
     public boolean isForBrowse() {
         return forBrowse;
     }
@@ -43,6 +47,29 @@ public class SQLServerSelect extends SQLSelect implements SQLServerObject {
         this.forXmlOptions = forXmlOptions;
     }
 
+    public SQLExpr getRowCount() {
+        return rowCount;
+    }
+
+    public void setRowCount(SQLExpr rowCount) {
+        if (rowCount != null) {
+            rowCount.setParent(this);
+        }
+        
+        this.rowCount = rowCount;
+    }
+
+    public SQLExpr getOffset() {
+        return offset;
+    }
+
+    public void setOffset(SQLExpr offset) {
+        if (offset != null) {
+            offset.setParent(this);
+        }
+        this.offset = offset;
+    }
+
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         this.accept0((SQLServerASTVisitor) visitor);
@@ -54,6 +81,8 @@ public class SQLServerSelect extends SQLSelect implements SQLServerObject {
             acceptChild(visitor, this.query);
             acceptChild(visitor, this.orderBy);
             acceptChild(visitor, this.hints);
+            acceptChild(visitor, this.offset);
+            acceptChild(visitor, this.rowCount);
         }
 
         visitor.endVisit(this);
@@ -65,31 +94,27 @@ public class SQLServerSelect extends SQLSelect implements SQLServerObject {
         int result = super.hashCode();
         result = prime * result + (forBrowse ? 1231 : 1237);
         result = prime * result + ((forXmlOptions == null) ? 0 : forXmlOptions.hashCode());
+        result = prime * result + ((offset == null) ? 0 : offset.hashCode());
+        result = prime * result + ((rowCount == null) ? 0 : rowCount.hashCode());
         return result;
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj) {
-            return true;
-        }
-        if (!super.equals(obj)) {
-            return false;
-        }
-        if (getClass() != obj.getClass()) {
-            return false;
-        }
+        if (this == obj) return true;
+        if (!super.equals(obj)) return false;
+        if (getClass() != obj.getClass()) return false;
         SQLServerSelect other = (SQLServerSelect) obj;
-        if (forBrowse != other.forBrowse) {
-            return false;
-        }
+        if (forBrowse != other.forBrowse) return false;
         if (forXmlOptions == null) {
-            if (other.forXmlOptions != null) {
-                return false;
-            }
-        } else if (!forXmlOptions.equals(other.forXmlOptions)) {
-            return false;
-        }
+            if (other.forXmlOptions != null) return false;
+        } else if (!forXmlOptions.equals(other.forXmlOptions)) return false;
+        if (offset == null) {
+            if (other.offset != null) return false;
+        } else if (!offset.equals(other.offset)) return false;
+        if (rowCount == null) {
+            if (other.rowCount != null) return false;
+        } else if (!rowCount.equals(other.rowCount)) return false;
         return true;
     }
 

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerSelectParser.java

@@ -91,6 +91,24 @@ public class SQLServerSelectParser extends SQLSelectParser {
                 throw new ParserException("syntax error, not support option : " + lexer.token());
             }
         }
+        
+        if (identifierEquals("OFFSET")) {
+            lexer.nextToken();
+            SQLExpr offset = this.expr();
+            
+            acceptIdentifier("ROWS");
+            select.setOffset(offset);
+            
+            if (identifierEquals("FETCH")) {
+                lexer.nextToken();
+                acceptIdentifier("NEXT");
+                
+                SQLExpr rowCount = expr();
+                acceptIdentifier("ROWS");
+                acceptIdentifier("ONLY");
+                select.setRowCount(rowCount);
+            }
+        }
 
         return select;
     }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/visitor/SQLServerOutputVisitor.java

@@ -595,6 +595,19 @@ public class SQLServerOutputVisitor extends SQLASTOutputVisitor implements SQLSe
                 }
             }
         }
+        
+        if (x.getOffset() != null) {
+            println();
+            print("OFFSET ");
+            x.getOffset().accept(this);
+            print(" ROWS");
+            
+            if (x.getRowCount() != null) {
+                print(" FETCH NEXT ");
+                x.getRowCount().accept(this);
+                print(" ROWS ONLY");
+            }
+        }
         return false;
     }