improved mysql parser support. for interval function

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java

@@ -497,8 +497,22 @@ public class MySqlExprParser extends SQLExprParser {
             }
 
             accept(Token.RPAREN);
-
-            return primaryRest(methodInvokeExpr);
+            
+            // 
+            
+            if (methodInvokeExpr.getParameters().size() == 1 // 
+                    && lexer.token() == Token.IDENTIFIER) {
+                SQLExpr value = methodInvokeExpr.getParameters().get(0);
+                String unit = lexer.stringVal();
+                lexer.nextToken();
+                
+                MySqlIntervalExpr intervalExpr = new MySqlIntervalExpr();
+                intervalExpr.setValue(value);
+                intervalExpr.setUnit(MySqlIntervalUnit.valueOf(unit.toUpperCase()));
+                return intervalExpr;
+            } else {
+                return primaryRest(methodInvokeExpr);
+            }
         } else {
             SQLExpr value = expr();
 

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlSelectTest_28.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 1999-2101 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.mysql;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.MysqlTest;
+import com.alibaba.druid.sql.SQLUtils;
+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;
+
+public class MySqlSelectTest_28 extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = "/* 0a7d0d8614637128401131809d4d9d/9// */"
+                + "SELECT id, name "
+                + "FROM `t_0248` AS `i_trash` "
+                + "WHERE `gmt_create` < DATE_ADD(NOW(), INTERVAL (- 7) DAY) "
+                + "LIMIT 0, 1000";
+
+        
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+//        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        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(1, visitor.getTables().size());
+        Assert.assertEquals(3, visitor.getColumns().size());
+        Assert.assertEquals(1, visitor.getConditions().size());
+        Assert.assertEquals(0, visitor.getOrderByColumns().size());
+        
+        {
+            String output = SQLUtils.toMySqlString(stmt);
+            Assert.assertEquals("SELECT id, name"
+                    + "\nFROM `t_0248` `i_trash`"
+                    + "\nWHERE `gmt_create` < DATE_ADD(NOW(), INTERVAL -7 DAY)"
+                    + "\nLIMIT 0, 1000", //
+                                output);
+        }
+        {
+            String output = SQLUtils.toMySqlString(stmt, SQLUtils.DEFAULT_LCASE_FORMAT_OPTION);
+            Assert.assertEquals("select id, name"
+                    + "\nfrom `t_0248` `i_trash`"
+                    + "\nwhere `gmt_create` < DATE_ADD(NOW(), interval -7 day)"
+                    + "\nlimit 0, 1000", //
+                                output);
+        }
+    }
+    
+    
+    
+}