Sql 查询将一列划分为多个列

我有以下情况： 在agents表中，我有两列，第一列称为AgentID，第二列称为AgentName。很少有AgentID以“A”开头，很少有AgentID以“M”开头，我想做的是：

AgentID AgentName
A123    Name1
M123    Name2
A234    Name3

Aagents AAgentName Magents MAgentName
A123    Name1      M123    Name2
A234    Name3      NULL    NULL

这可能吗？我知道这很奇怪，但我的老板希望这样

试试这个

select * from (select AgentID as Aagents, AgentName as AagentName from table where 
AgentID like 'A%'), (select AgentID as MAgents, AgentName as MAgentName from 
table where AgentID like 'M%')

大概是这样的：

select 
case when AgentName like 'A%' then name end as Aagents,
case when AgentName like 'M%' then Name end as Magents
from tblName

---

您可以在两个子查询（一个用于a代理，一个用于M代理）和

ROW\u NUMBER（）

上的联接之间进行完全外部联接，以使一侧具有空值（记录较少的一侧）：

试试这个

WITH AAgents AS
(
  SELECT ROW_NUMBER() over (order by AgentID) AS RN,
         AgentID AS Aagents,
         AgentName As AAgentName
  FROM Agents
  WHERE LEFT(AgentID,1)='A'
),
MAgents As
(
  SELECT ROW_NUMBER() over (order by AgentID) AS RN,
         AgentID AS Magents,
         AgentName As MAgentName
  FROM Agents
  WHERE LEFT(AgentID,1)='M'
)

SELECT
  Aagents,
  AAgentName,
  Magents,
  MAgentName
FROM AAgents
FULL OUTER JOIN MAgents
ON AAgents.RN=MAgents.RN

---

您的答案与我的答案非常相似，但您使用了CTE而不是子查询。出于好奇：在这种情况下使用CTE有什么好处？

WITH AAgents AS
(
  SELECT ROW_NUMBER() over (order by AgentID) AS RN,
         AgentID AS Aagents,
         AgentName As AAgentName
  FROM Agents
  WHERE LEFT(AgentID,1)='A'
),
MAgents As
(
  SELECT ROW_NUMBER() over (order by AgentID) AS RN,
         AgentID AS Magents,
         AgentName As MAgentName
  FROM Agents
  WHERE LEFT(AgentID,1)='M'
)

SELECT
  Aagents,
  AAgentName,
  Magents,
  MAgentName
FROM AAgents
FULL OUTER JOIN MAgents
ON AAgents.RN=MAgents.RN