sql里面pivot函数怎么用，举个例子

Pivot 函数可以将行数据转换为列数据，可以使用以下语法：

SELECT *
FROM (
SELECT [列1], [列2], [值]
FROM [表名]
) AS [源表]
PIVOT (
[聚合函数]([值])
FOR [列名] IN ([列1], [列2], ...)
) AS [结果表]

例如，假设有一个表格名为 Sales，包含以下数据：

| Region | Product | Sales |
|--------|---------|-------|
| East | Apple | 100 |
| East | Banana | 200 |
| West | Apple | 150 |
| West | Banana | 250 |

我们可以使用 Pivot 函数将其转换为以下形式：

| Region | Apple | Banana |
|--------|-------|--------|
| East | 100 | 200 |
| West | 150 | 250 |

具体的 SQL 语句如下：

SELECT *
FROM (
SELECT Region, Product, Sales
FROM Sales
) AS SourceTable
PIVOT (
SUM(Sales)
FOR Product IN (Apple, Banana)
) AS PivotTable