Question

我试图连接一些球员没有中间名的球员的名字。在连接如下时，我为没有中间名的玩家获得了一个空白区域，并且逻辑适用于具有中间名的玩家。如何仅为NULL值列删除不需要的空格？

我只想在concatenate表达式中使用中间名的Initial。

SELECT m_playerid, first_name + ' ' + SUBSTRING (coalesce (middle_
name, ' '), 1,1) + ' ' + last_name as [Full name]
, game as Game, inns as Innings, [scores] as Scores FROM  odsports

我不应该引入条件来删除空格为NULL？我很震惊！

Answer 1

您可以使用NULL与+运算符连接的任何内容生成NULL这一事实，而CONCAT函数将NULL转换为空字符串

所以CONCAT(first_name, ' ', LEFT(middle_name,1) + ' ', last_name)将根据需要处理空中间名 - 如下例

WITH T(first_name, middle_name, last_name) AS
(
SELECT 'Franklin', 'Delano', 'Roosevelt' union all
SELECT 'Barack', NULL, 'Obama'
)
SELECT CONCAT(first_name, ' ', LEFT(middle_name,1) + ' ', last_name)
FROM T

返回

+----------------------+
|   (No column name)   |
+----------------------+
| Franklin D Roosevelt |
| Barack Obama         |
+----------------------+

Answer 2

为双空格添加替换，以及使用isnull函数。试试这个

SELECT 
m_playerid, 
REPLACE(
LTRIM(RTRIM(ISNULL(first_name ,'')))
+CASE WHEN middle_name IS NULL
        THEN ' '
    ELSE ' '+LEFT(ISNULL(middle_name,' '),1)+' ' END
+
LTRIM(RTRIM(ISNULL(last_name,'')))
,'  ',' ') as [Full name],
game as Game, 
inns as Innings, 
[scores] as Scores 
FROM  odsports

Answer 3

试试这个：

SELECT  m_playerid,
    COALESCE(first_name + ' ' + middle_name + ' ' + last_name,
             first_name + ' ' + last_name,
             first_name,
             last_name) as [Full name],
    game as Game, 
    inns as Innings, 
    [scores] as Scores
FROM odsports

Answer 4

SELECT 
   m_playerid, 
   LTRIM(CONCAT(first_name,Space(1),LTRIM(RTRIM(middle_name+space(1)+last_name)))) 
                                                                         as [Full name],
   game as Game,
   inns as Innings, 
   [scores] as Scores 
FROM  odsports

如何在连接时删除空格，而有些空值为Null？

4 个答案: