这两种方法如下所示:CREATE TABLE db.tablename1 STORED AS ORC ASFROM db.tablename2;CREATEEXTERNAL TABLE IF NOT EXISTS db.tablename1 var2 STRINGSTORED AS ORCSELECT
$query = "SELECT * FROM test_table WHERE test_no=12345";$count =$query = "SELECT COUNT(test) AS count FROM test_table WHERE test_no=12345";$result = $queryResult->fetch();
if($resul
我对SQL不是很熟悉,请给我解释一下下面两个的区别,什么是最好的使用方法。使用一种比使用另一种有什么优势吗?CREATE TABLE Employee Emp_Id int NOT NULL, ...FOREIGN KEY (Dep_Id) REFERENCES Department(Dep_Id)和(
Emp_Id int NOT NULL