Question

查询：

SELECT TOP (1) '-1' AS hrempid, 'All employees' AS fullname
FROM employee
UNION
SELECT fullname, hrempid
FROM employee AS employee1 
order by fullname

错误：将数据类型varchar转换为bigint时出错。

Answer 1

union之后，您的列的顺序错误。这是更正版本：

SELECT   TOP (1) '-1' AS hrempid, 'All employees' AS fullname
FROM     employee
UNION
SELECT   hrempid, fullname
FROM     employee AS employee1 
ORDER BY fullname

更好的是，使用这样的东西：

SELECT   CAST(-1 AS BIGINT) AS hrempid, 'All employees' AS fullname
UNION ALL
SELECT   hrempid, fullname
FROM     employee AS employee1 
ORDER BY fullname

Answer 2

将'保留在hrempid周围并切换列。试试这个：

SELECT TOP (1) 'All employees' AS fullname, -1 AS hrempid
FROM employee
UNION
SELECT fullname, hrempid
FROM employee AS employee1 
order by fullname

使用union将数据类型varchar转换为bigint时出错

2 个答案: