添加SQL统计功能，统计SQL中所使用的表和字段

git-svn-id: http://code.alibabatech.com/svn/druid/trunk@267 b9813039-fb51-4c41-a8b9-e21c2acb5095

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

@@ -30,6 +30,16 @@ public class MySqlSchemaStatVisitor extends MySqlASTVisitorAdapter {
     private final static ThreadLocal<String>              currentTableLocal = new ThreadLocal<String>();
     private final static ThreadLocal<Mode>                modeLocal         = new ThreadLocal<Mode>();
 
+    public boolean visit(SQLSubqueryTableSource x) {
+        Map<String, String> aliasMap = aliasLocal.get();
+        if (aliasMap != null) {
+            if (x.getAlias() != null) {
+                aliasMap.put(x.getAlias(), null);
+            }
+        }
+        return true;
+    }
+
     public boolean visit(SQLExprTableSource x) {
         if (x.getExpr() instanceof SQLIdentifierExpr) {
             String ident = ((SQLIdentifierExpr) x.getExpr()).getName();
@@ -91,10 +101,10 @@ public class MySqlSchemaStatVisitor extends MySqlASTVisitorAdapter {
 
         Map<String, String> aliasMap = aliasLocal.get();
         aliasMap.put(ident, ident);
-        
+
         accept(x.getItems());
         accept(x.getWhere());
-        
+
         return false;
     }
 
@@ -240,12 +250,12 @@ public class MySqlSchemaStatVisitor extends MySqlASTVisitorAdapter {
     }
 
     public boolean visit(SQLSelectQueryBlock x) {
-        
+
         if (x.getFrom() instanceof SQLSubqueryTableSource) {
             x.getFrom().accept(this);
             return false;
         }
-        
+
         x.putAttribute("_original_use_mode", modeLocal.get());
         modeLocal.set(Mode.Select);
 
@@ -281,10 +291,16 @@ public class MySqlSchemaStatVisitor extends MySqlASTVisitorAdapter {
         if (x.getOwner() instanceof SQLIdentifierExpr) {
             String owner = ((SQLIdentifierExpr) x.getOwner()).getName();
 
-            Map<String, String> aliasMap = aliasLocal.get();
-            if (aliasMap != null) {
-                String table = aliasMap.get(owner);
-                fields.add(new Column(table, x.getName()));
+            if (owner != null) {
+                Map<String, String> aliasMap = aliasLocal.get();
+                if (aliasMap != null) {
+                    String table = aliasMap.get(owner);
+                    
+                    // table == null时是SubQuery
+                    if (table != null) {
+                        fields.add(new Column(table, x.getName()));
+                    }
+                }
             }
         }
         return false;

src/test/java/com/alibaba/druid/sql/mysql/bvt/visitor/MySqlSchemaStatVisitorTest_Subquery2.java

@@ -0,0 +1,44 @@
+package com.alibaba.druid.sql.mysql.bvt.visitor;
+
+import java.util.List;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlSchemaStatVisitor.Column;
+
+public class MySqlSchemaStatVisitorTest_Subquery2 extends TestCase {
+
+    public void test_0() throws Exception {
+        String sql = "SELECT a.id, a.name, b.name groupName FROM (select id, name, groupId from users limit 10) a inner join groups b on a.groupId = b.id";
+
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement statemen = statementList.get(0);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        statemen.accept(visitor);
+
+        System.out.println(sql);
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getFields());
+
+        Assert.assertEquals(2, visitor.getTables().size());
+        Assert.assertEquals(true, visitor.getTables().containsKey("users"));
+        Assert.assertEquals(true, visitor.getTables().containsKey("groups"));
+
+        Assert.assertEquals(5, visitor.getFields().size());
+        Assert.assertEquals(true, visitor.getFields().contains(new Column("users", "id")));
+        Assert.assertEquals(true, visitor.getFields().contains(new Column("users", "groupId")));
+        Assert.assertEquals(true, visitor.getFields().contains(new Column("users", "name")));
+        Assert.assertEquals(true, visitor.getFields().contains(new Column("groups", "id")));
+        Assert.assertEquals(true, visitor.getFields().contains(new Column("groups", "name")));
+
+    }
+
+}