sql parser support drop table

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

@@ -111,12 +111,24 @@ public class SQLStatementParser extends SQLParser {
 
                 if (lexer.token() == Token.TABLE) {
                     lexer.nextToken();
-                    SQLName name = this.exprParser.name();
-                    statementList.add(new SQLDropTableStatement(name));
+
+                    SQLDropTableStatement stmt = new SQLDropTableStatement();
+
+                    for (;;) {
+                        SQLName name = this.exprParser.name();
+                        stmt.getTableNames().add(name);
+                        if (lexer.token() == Token.COMMA) {
+                            lexer.nextToken();
+                            continue;
+                        }
+                        break;
+                    }
+
+                    statementList.add(stmt);
                     continue;
                 }
             }
-            
+
             if (lexer.token() == Token.TRUNCATE) {
                 SQLStatement stmt = parseTruncate();
                 statementList.add(stmt);
@@ -136,9 +148,9 @@ public class SQLStatementParser extends SQLParser {
             throw new ParserException("TODO " + lexer.token());
         }
     }
-    
+
     public SQLStatement parseTruncate() {
-    	throw new ParserException("TODO " + lexer.token());
+        throw new ParserException("TODO " + lexer.token());
     }
 
     public SQLStatement parseInsert() {

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

@@ -14,6 +14,7 @@ import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
 import com.alibaba.druid.sql.ast.expr.SQLPropertyExpr;
 import com.alibaba.druid.sql.ast.statement.SQLDeleteStatement;
+import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLInsertStatement;
 import com.alibaba.druid.sql.ast.statement.SQLJoinTableSource;
@@ -65,6 +66,36 @@ public class SchemaStatVisitor extends SQLASTVisitorAdapter {
 
         return false;
     }
+    
+    @Override
+    public boolean visit(SQLDropTableStatement x) {
+        x.putAttribute("_original_use_mode", modeLocal.get());
+        modeLocal.set(Mode.Insert);
+
+        aliasLocal.set(new HashMap<String, String>());
+
+        String originalTable = currentTableLocal.get();
+
+        for (SQLName name : x.getTableNames()) {
+            String ident = name.toString();
+            currentTableLocal.set(ident);
+            x.putAttribute("_old_local_", originalTable);
+
+            TableStat stat = tableStats.get(ident);
+            if (stat == null) {
+                stat = new TableStat();
+                tableStats.put(new TableStat.Name(ident), stat);
+            }
+            stat.incrementDropCount();
+
+            Map<String, String> aliasMap = aliasLocal.get();
+            if (aliasMap != null) {
+                aliasMap.put(ident, ident);
+            }
+        }
+
+        return false;
+    }
 
     @Override
     public boolean visit(SQLInsertStatement x) {

src/main/java/com/alibaba/druid/stat/TableStat.java

@@ -21,6 +21,19 @@ public class TableStat {
     int updateCount = 0;
     int deleteCount = 0;
     int insertCount = 0;
+    int dropCount   = 0;
+
+    public int getDropCount() {
+        return dropCount;
+    }
+    
+    public void incrementDropCount() {
+        dropCount++;
+    }
+
+    public void setDropCount(int dropCount) {
+        this.dropCount = dropCount;
+    }
 
     public int getSelectCount() {
         return selectCount;
@@ -73,16 +86,19 @@ public class TableStat {
     public String toString() {
         StringBuilder buf = new StringBuilder(4);
         if (insertCount > 0) {
-            buf.append("C");
+            buf.append("Insert");
         }
         if (updateCount > 0) {
-            buf.append("U");
+            buf.append("Update");
         }
         if (selectCount > 0) {
-            buf.append("R");
+            buf.append("Selelct");
         }
         if (deleteCount > 0) {
-            buf.append("D");
+            buf.append("Delete");
+        }
+        if (dropCount > 0) {
+            buf.append("Drop");
         }
 
         return buf.toString();