UNION with IF语句

Question

我正在编写一个查询，它对数据库表执行各种检查，并返回结果的摘要(在单个结果集中)

IF ( select COUNT(*) from member_table WHERE password IS NULL ) > 0
   SELECT 'password check' as name, 'ERROR' as result ,'there is user(s) with blank password' as description
ELSE
   SELECT 'password check' as name, 'COMPLETED' as result, 'OK' as description

UNION

IF ( select COUNT(*) from server_context_properties ) = 0
   SELECT 'context properties check' as name, 'ERROR' as result ,'no context property has been entered' as description
ELSE
   SELECT 'context properties check' as name, 'COMPLETED' as result, 'OK' as description

结果表应如下所示：

name                    result  description
password check          COMPLETED   OK
contex properties check ERROR       no context property has been entered

我知道语法是不正确的，但我想不出任何方法来实现这一点。

Answer 1

Select Properties.Name, Properties.Result, Properties.Description
From    (
        Select 'password check', 1 As value, 'ERROR' As Result, 'There is a user with a blank password' As Description
        Union All Select 'password check', 0, 'COMPLETED', 'OK'
        Union All Select 'context properties check', 0, 'ERROR', 'No context property has been entered'
        Union All Select 'context properties check', 1, 'COMPLETED', 'OK'
        ) As Properties
    Join    (
            Select 'password check' As name
                , Case
                    When Exists( Select 1 From member_table Where password Is Null ) Then 1
                    Else 0
                    End As Value
            Union All 
            Select 'context properties check'
                , Case
                    When Exists( Select 1 From server_context_properties ) Then 1
                    Else 0
                    End
            ) As Results
        On Results.Name = Properties.Name
            And Results.Value = Properties.Value

Answer 2

您可以尝试这样做：

DECLARE @passwordcheck INT, @contextcheck INT

SELECT @passwordcheck = COUNT(*) 
FROM member_table 
WHERE [password] IS NULL

SELECT @contextcheck = COUNT(*) 
FROM server_context_properties

SELECT  'password check' as name, 
        CASE WHEN @passwordcheck > 0 THEN 'ERROR' ELSE 'COMPLETED' END as result,
        CASE WHEN @passwordcheck > 0 THEN 'there is user(s) with blank password' ELSE 'OK' as description
UNION
SELECT  'context properties check' as name, 
        CASE WHEN @contextcheck = 0 THEN 'ERROR' ELSE 'COMPLETED' END as result,
        CASE WHEN @contextcheck = 0 THEN 'no context property has been entered' ELSE 'OK' END as description

Answer 3

也许可以这样做：

SELECT 'password check' as name, 'ERROR' as result ,'there is user(s) with blank password' as description
WHERE EXISTS ( select * from member_table WHERE password IS NULL )
UNION
SELECT 'password check' as name, 'ERROR' as result ,'there is user(s) with blank password' as description
WHERE NOT EXISTS ( select * from member_table WHERE password IS NULL )

UNION

SELECT 'context properties check' as name, 'ERROR' as result ,'no context property has been entered' as description
WHERE NOT EXISTS (select * from server_context_properties)
UNION
SELECT 'context properties check' as name, 'COMPLETED' as result, 'OK' as description
WHERE EXISTS (select * from server_context_properties)