在mysql中显示的列

Question

我试图构建一个查询，显示第一个&姓氏&“打开者”的标签。这里的查询：

SELECT a.account_id, 
     a.cust_id, 
     a.last_activity_date, 
     a.open_emp_id, 
     Concat(' Opened By ', e.fname, ' ', e.lname), 
     a.avail_balance 
FROM account a 
     INNER JOIN employee e 
       ON a.open_emp_id = e. emp_id 
WHERE NOT EXISTS (SELECT 1 
        FROM transaction t 
        WHERE t.txn_date = a.last_activity_date); 

这只是伟大工程列标签上写着CONCAT(' Opened By ', e.fname, ' ', e.lname)，而不是仅仅e.fname & e.lname。

Answer 1

你可以使用AS关键字来命名您的列：

SELECT a.account_id, a.cust_id, a.last_activity_date, a.open_emp_id, 
CONCAT(' Opened By ', e.fname, ' ', e.lname) AS opened_by, a.avail_balance 
FROM account a INNER JOIN employee e 
ON a.open_emp_id = e. emp_id 
WHERE NOT EXISTS (SELECT 1 
FROM transaction t 
WHERE t.txn_date = a.last_activity_date); 

Answer 2

使用别名：

CONCAT(' Opened By ', e.fname, ' ', e.lname) AS opened_by 

现在，您可以参考这个结果，如果它是从一个叫opened_by

Answer 3

使用别名列...

... 
Concat(' Opened By ', e.fname, ' ', e.lname) AS 'openedBy', 
...