From d3266ca300a9585e84aedf93b5448e314cc2edc8 Mon Sep 17 00:00:00 2001
From: wenshao <szujobs@hotmail.com>
Date: Wed, 31 Jan 2018 17:51:20 +0800
Subject: [PATCH] bug fixed for db2 sql parser. for issue #2304

---
 .../sql/dialect/db2/parser/DB2ExprParser.java |  9 +++
 .../druid/bvt/sql/db2/DB2SetTest_0.java       | 64 +++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 src/test/java/com/alibaba/druid/bvt/sql/db2/DB2SetTest_0.java

diff --git a/src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2ExprParser.java b/src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2ExprParser.java
index f5cc445f14..944251bd2d 100644
--- a/src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2ExprParser.java
+++ b/src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2ExprParser.java
@@ -107,6 +107,15 @@ public class DB2ExprParser extends SQLExprParser {
                     expr = new SQLIdentifierExpr("CURRENT TIME");
                 }
             }
+        } else if (lexer.token() == Token.SCHEMA) {
+            if (expr instanceof SQLIdentifierExpr) {
+                SQLIdentifierExpr identExpr = (SQLIdentifierExpr) expr;
+                if (identExpr.hashCode64() == FnvHash.Constants.CURRENT) {
+                    lexer.nextToken();
+
+                    expr = new SQLIdentifierExpr("CURRENT SCHEMA");
+                }
+            }
         } else if (lexer.identifierEquals(FnvHash.Constants.MONTHS)) {
             SQLIntervalExpr intervalExpr = new SQLIntervalExpr(expr, SQLIntervalUnit.MONTH);
             lexer.nextToken();
diff --git a/src/test/java/com/alibaba/druid/bvt/sql/db2/DB2SetTest_0.java b/src/test/java/com/alibaba/druid/bvt/sql/db2/DB2SetTest_0.java
new file mode 100644
index 0000000000..126375c630
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/sql/db2/DB2SetTest_0.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 1999-2017 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.db2;
+
+import com.alibaba.druid.sql.DB2Test;
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.db2.parser.DB2StatementParser;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2SchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+import com.alibaba.druid.util.JdbcConstants;
+import org.junit.Assert;
+
+import java.util.List;
+
+public class DB2SetTest_0 extends DB2Test {
+
+    public void test_0() throws Exception {
+        String sql = "set current schema = 'PAYROLL'";
+
+        DB2StatementParser parser = new DB2StatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+//        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        DB2SchemaStatVisitor visitor = new DB2SchemaStatVisitor();
+        stmt.accept(visitor);
+
+//        System.out.println("Tables : " + visitor.getTables());
+//        System.out.println("fields : " + visitor.getColumns());
+//        System.out.println("coditions : " + visitor.getConditions());
+//        System.out.println("orderBy : " + visitor.getOrderByColumns());
+
+        Assert.assertEquals(0, visitor.getTables().size());
+        Assert.assertEquals(0, visitor.getColumns().size());
+        Assert.assertEquals(0, visitor.getConditions().size());
+
+//        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("DSN81010.EMP")));
+
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "last_name")));
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "first_name")));
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "full_name")));
+
+        Assert.assertEquals("SET CURRENT SCHEMA = 'PAYROLL'", //
+                            SQLUtils.toSQLString(stmt, JdbcConstants.DB2));
+        Assert.assertEquals("set CURRENT SCHEMA = 'PAYROLL'", //
+                            SQLUtils.toSQLString(stmt, JdbcConstants.DB2, SQLUtils.DEFAULT_LCASE_FORMAT_OPTION));
+    }
+}