Question

JOB        ENAME
--------  ----------
ANALYST    SCOTT
ANALYST    FORD
CLERK      SMITH
CLERK      ADAMS
CLERK      MILLER
CLERK      JAMES
MANAGER    JONES
MANAGER    CLARK
MANAGER    BLAKE
PRESIDENT  KING
SALESMAN   ALLEN
SALESMAN   MARTIN
SALESMAN   TURNER
SALESMAN   WARD

我想格式化结果集，以便每个作业都有自己的列：

CLERKS  ANALYSTS  MGRS   PREZ  SALES
------  --------  -----  ----  ------
MILLER  FORD      CLARK  KING  TURNER
JAMES   SCOTT     BLAKE        MARTIN
ADAMS             JONES        WARD
SMITH

我试过

SELECT ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN from
(
  SELECT ename, job from emp
) as st
pivot
(
  SELECT ename
  FOR job in (ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN)
) as pivottable

我收到了这些错误

Msg 156，Level 15，State 1，Line 7
  关键字'SELECT'附近的语法不正确。
  Msg 156，Level 15，State 1，Line 8
  关键字'in'附近的语法不正确。

如何使用数据透视表在数据透视列下对字符串进行分组？

Answer 1

使用PIVOT函数时，需要使用聚合函数。 PIVOT的语法是：

来自MSDN：

SELECT <non-pivoted column>,
    [first pivoted column] AS <column name>,
    [second pivoted column] AS <column name>,
    [last pivoted column] AS <column name>
FROM
    (<SELECT query that produces the data>)
    AS <alias for the source query>
PIVOT
(
    <aggregation function>(<column being aggregated>)
FOR
[<column that contains the values that will become column headers>]
    IN ( [first pivoted column], [second pivoted column],
    ... [last pivoted column])
) AS <alias for the pivot table>
<optional ORDER BY clause>;

使用字符串，您需要使用MIN()或MAX()聚合函数。您将遇到的问题是这些函数将为每列返回一个值。

因此，为了让PIVOT生效，您需要提供一个明确的值，以便在GROUP BY期间保持行分开。

对于您的示例，您可以使用row_number()：

SELECT ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN 
from
(
  SELECT ename, job,
    row_number() over(partition by job order by ename) rn
  from emp
) as st
pivot
(
  max(ename)
  FOR job in (ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN)
) as pivottable

请参阅SQL Fiddle with Demo。

row_number()创建了一个分配给job中每一行的不同值，当您应用聚合函数时，GROUP BY中的PIVOT仍将保留获得单独的行。

枢轴列下的数据透视表字符串分组？

1 个答案: