improve mysql ddl parser

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/statement/MySqlPartitionByHash.java

@@ -31,6 +31,8 @@ public class MySqlPartitionByHash extends MySqlObjectImpl implements SQLPartitio
 
     private SQLExpr           partitionCount;
 
+    private boolean           linear;
+
     @Override
     public void accept0(MySqlASTVisitor visitor) {
         if (visitor.visit(this)) {
@@ -48,13 +50,20 @@ public class MySqlPartitionByHash extends MySqlObjectImpl implements SQLPartitio
         this.partitionCount = partitionCount;
     }
 
-    
     public SQLExpr getExpr() {
         return expr;
     }
 
-    
     public void setExpr(SQLExpr expr) {
         this.expr = expr;
     }
+
+    public boolean isLinear() {
+        return linear;
+    }
+
+    public void setLinear(boolean linear) {
+        this.linear = linear;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/statement/MySqlPartitionByKey.java

@@ -32,6 +32,8 @@ public class MySqlPartitionByKey extends MySqlObjectImpl implements SQLPartition
 
     private SQLExpr           partitionCount;
 
+    private boolean           linear;
+
     @Override
     public void accept0(MySqlASTVisitor visitor) {
         if (visitor.visit(this)) {
@@ -57,4 +59,12 @@ public class MySqlPartitionByKey extends MySqlObjectImpl implements SQLPartition
         this.columns = columns;
     }
 
+    public boolean isLinear() {
+        return linear;
+    }
+
+    public void setLinear(boolean linear) {
+        this.linear = linear;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlCreateTableParser.java

@@ -355,10 +355,21 @@ public class MySqlCreateTableParser extends SQLCreateTableParser {
             if (identifierEquals("PARTITION")) {
                 lexer.nextToken();
                 accept(Token.BY);
+                
+                boolean linera = false;
+                if (identifierEquals("LINEAR")) {
+                    lexer.nextToken();
+                    linera = true;
+                }
 
                 if (lexer.token() == Token.KEY) {
                     MySqlPartitionByKey clause = new MySqlPartitionByKey();
                     lexer.nextToken();
+                    
+                    if (linera) {
+                        clause.setLinear(true);
+                    }
+                    
                     accept(Token.LPAREN);
                     for (;;) {
                         clause.getColumns().add(this.exprParser.name());
@@ -379,6 +390,10 @@ public class MySqlCreateTableParser extends SQLCreateTableParser {
                     lexer.nextToken();
                     MySqlPartitionByHash clause = new MySqlPartitionByHash();
                     
+                    if (linera) {
+                        clause.setLinear(true);
+                    }
+                    
                     accept(Token.LPAREN);
                     clause.setExpr(this.exprParser.expr());
                     accept(Token.RPAREN);

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlOutputVisitor.java

@@ -1496,7 +1496,11 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public boolean visit(MySqlPartitionByKey x) {
-        print("PARTITION BY KEY (");
+        if (x.isLinear()) {
+            print("PARTITION BY LINEAR KEY (");
+        } else {
+            print("PARTITION BY KEY (");
+        }
         printAndAccept(x.getColumns(), ", ");
         print(")");
 
@@ -1514,7 +1518,12 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public boolean visit(MySqlPartitionByHash x) {
-        print("PARTITION BY HASH (");
+        if (x.isLinear()) {
+            print("PARTITION BY LINEAR HASH (");
+        } else {
+            print("PARTITION BY HASH (");
+        }
+        // 
         x.getExpr().accept(this);
         print(")");