Merge pull request #843 from wenshao/master

improved postgresql support

src/main/java/com/alibaba/druid/sql/dialect/postgresql/parser/PGSQLStatementParser.java

@@ -299,7 +299,9 @@ public class PGSQLStatementParser extends SQLStatementParser {
     }
 
     protected SQLAlterTableAlterColumn parseAlterColumn() {
-        accept(Token.COLUMN);
+        if (lexer.token() == Token.COLUMN) {
+            lexer.nextToken();
+        }
 
         SQLColumnDefinition column = this.exprParser.parseColumn();
 

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

@@ -796,6 +796,9 @@ public class SQLStatementParser extends SQLParser {
                     if (lexer.token() == Token.COLUMN) {
                         SQLAlterTableAlterColumn alterColumn = parseAlterColumn();
                         stmt.getItems().add(alterColumn);
+                    } else if (lexer.token() == Token.LITERAL_ALIAS) {
+                        SQLAlterTableAlterColumn alterColumn = parseAlterColumn();
+                        stmt.getItems().add(alterColumn);
                     } else {
                         throw new ParserException("TODO " + lexer.token() + " " + lexer.stringVal());
                     }

src/test/java/com/alibaba/druid/bvt/sql/postgresql/PGAlterTableTest1.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 1999-2011 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.postgresql;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.PGTest;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.postgresql.parser.PGSQLStatementParser;
+import com.alibaba.druid.sql.dialect.postgresql.visitor.PGSchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+
+public class PGAlterTableTest1 extends PGTest {
+
+    public void test_0() throws Exception {
+        String sql = "ALTER TABLE \"measure_data\" ALTER \"measure_id\" DROP NOT NULL";
+
+        PGSQLStatementParser parser = new PGSQLStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement statemen = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        PGSchemaStatVisitor visitor = new PGSchemaStatVisitor();
+        statemen.accept(visitor);
+
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getColumns());
+
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("measure_data")));
+        
+        Assert.assertTrue(visitor.getTables().get(new TableStat.Name("measure_data")).getAlterCount() == 1);
+
+        Assert.assertTrue(visitor.getColumns().size() == 1);
+    }
+
+   
+}