postgres交叉表查询中的动态列名

SELECT
    category,
    MAX(CASE WHEN month = 'January' THEN sales END) AS january_sales,
    MAX(CASE WHEN month = 'February' THEN sales END) AS february_sales,
    MAX(CASE WHEN month = 'March' THEN sales END) AS march_sales
FROM
    sales_table
GROUP BY
    category;

SELECT *
FROM crosstab(
    'SELECT category, month, sales
     FROM sales_table
     ORDER BY 1, 2',
    'VALUES (''January''::text), (''February''::text), (''March''::text)'
) AS ct (category text, january_sales numeric, february_sales numeric, march_sales numeric);