improved sql parser.

src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java

@@ -36,6 +36,9 @@ public class SQLPropertyExpr extends SQLExprImpl implements SQLName {
     }
 
     public SQLPropertyExpr(SQLExpr owner, String name){
+        if (name == null) {
+            throw new IllegalArgumentException("name is null.");
+        }
         setOwner(owner);
         this.name = name;
     }
@@ -59,8 +62,8 @@ public class SQLPropertyExpr extends SQLExprImpl implements SQLName {
     }
 
     public String getOwnernName() {
-        if (owner instanceof SQLIdentifierExpr) {
-            return ((SQLIdentifierExpr) owner).getName();
+        if (owner instanceof SQLName) {
+            return ((SQLName) owner).toString();
         }
 
         return null;

src/main/java/com/alibaba/druid/sql/ast/statement/SQLExprTableSource.java

@@ -197,22 +197,9 @@ public class SQLExprTableSource extends SQLTableSourceImpl {
     }
 
     public boolean containsAlias(String alias) {
-        if (SQLUtils.nameEquals(this.alias, alias)) {
-            return true;
-        }
+        long hashCode64 = FnvHash.hashCode64(alias);
 
-        String name = null;
-        if (expr instanceof SQLIdentifierExpr) {
-            name = ((SQLIdentifierExpr) expr).getName();
-        } else if (expr instanceof SQLPropertyExpr) {
-            name = ((SQLPropertyExpr) expr).getName();
-        }
-
-        if (name != null && SQLUtils.nameEquals(name, alias)) {
-            return true;
-        }
-
-        return false;
+        return containsAlias(hashCode64);
     }
 
     public boolean containsAlias(long aliasHash) {
@@ -220,9 +207,16 @@ public class SQLExprTableSource extends SQLTableSourceImpl {
             return true;
         }
 
+        if (expr instanceof SQLPropertyExpr) {
+            long exprNameHash = ((SQLPropertyExpr) expr).hashCode64();
+            if (exprNameHash == aliasHash) {
+                return true;
+            }
+        }
+
         if (expr instanceof SQLName) {
             long exprNameHash = ((SQLName) expr).nameHashCode64();
-            return exprNameHash == aliasHashCod64;
+            return exprNameHash == aliasHash;
         }
 
         return false;

src/main/java/com/alibaba/druid/sql/ast/statement/SQLJoinTableSource.java

@@ -459,11 +459,13 @@ public class SQLJoinTableSource extends SQLTableSourceImpl implements SQLReplace
             return false;
         }
 
-        if (left.containsAlias(alias_a) && right.containsAlias(alias_b)) {
+        if (left.containsAlias(alias_a)
+                && right.containsAlias(alias_b)) {
             return true;
         }
 
-        return right.containsAlias(alias_a) && left.containsAlias(alias_b);
+        return right.containsAlias(alias_a)
+                && left.containsAlias(alias_b);
     }
 
     public boolean conditionContainsTable(String alias) {
@@ -499,4 +501,16 @@ public class SQLJoinTableSource extends SQLTableSourceImpl implements SQLReplace
 
         return right.findTableSource(alias_hash);
     }
+
+    public SQLTableSource other(SQLTableSource x) {
+        if (left == x) {
+            return right;
+        }
+
+        if (right == x) {
+            return left;
+        }
+
+        return null;
+    }
 }

src/main/java/com/alibaba/druid/sql/repository/SchemaResolveVisitorFactory.java

@@ -1649,6 +1649,10 @@ class SchemaResolveVisitorFactory {
 
             if (ctxTable instanceof SQLJoinTableSource) {
                 String alias = tableSource.computeAlias();
+                if (alias == null) {
+                    return;
+                }
+
                 SQLPropertyExpr propertyExpr = new SQLPropertyExpr(new SQLIdentifierExpr(alias), ident, hash);
                 propertyExpr.setResolvedColumn(x.getResolvedColumn());
                 propertyExpr.setResolvedTableSource(x.getResolvedTableSource());