SQL，具有多个参数的Case [英] SQL, Case with multiple parameters

问题描述

我对sql相对较新，我一直在尝试获得一些我认为我的编程背景没有帮助的东西。请帮我一些例子。

我需要根据是否有2个ID的可能性来构建一个带有字符串串联的return语句



到目前为止，我已经得到了这个：

Hi, I'm relatively new to sql and I've been trying to get something which I think my programming background is not helping. Please help me with some examples.
I need to build a return statement with the concatenation of strings based on the possibilities of having or not 2 IDs

So far I've got this:

SELECT
....
  ,'ON VESSEL "' + VESSEL.NAME + '" FROM '
   + ORIGIN.NAME + '/' + ORIGIN.COUNTRY_NAME + 'TO'
   + CASE ISNULL(SHIP.TRANSSHIP_PORT_ID_1,0)
     WHEN 0 THEN
         ''
     ELSE
         PORT1.NAME + '/' + PORT1.COUNTRY_NAME
         + CASE ISNULL(SHIP.TRANSSHIP_PORT_ID_2,0) +
           WHEN 0 THEN
               ''
           ELSE
               ' AND TO ' 
               + PORT2.NAME + '/' + PORT2.COUNTRY_NAME
           END
         + 'IN TRANSIT TO' 
     END  
   + DESTINATION.NAME + '/' + DESTINATION.COUNTRY_NAME
FROM
....

事情是，到目前为止，没有什么能阻止用户删除第一个记录。这会导致逻辑错误。

有没有办法做类似的事情：

The thing is, so far there is nothing stopping the user to delete the first record. Which would cause an error with the logic.
Is there a way to do something like:

CASE condition
WHEN test AND A = B THEN

到目前为止，由于AND，我收到错误...





提前谢谢

So far I get an error due to the "AND"...


Thanks in advance

推荐答案

你可能是得到语法错误接近AND...问题出在 test 你需要一个布尔表达式...像test ='Y'

SQL服务器没有布尔数据类型



看看这个链接 http://blog.sqlauthority.com/2007/04/14/sql-server-case-statementexpression-examples - 和 - 解释/ [ ^ ]

或此参考资料 [ ^ ]

You are probably getting a syntax error "near to AND" ... the problem is with test You need a Boolean expression in there ... something like "test='Y'"
SQL server does not have a Boolean Data Type

Have a look at this link http://blog.sqlauthority.com/2007/04/14/sql-server-case-statementexpression-examples-and-explanation/[^]
or this reference material[^]

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