mysql - 如何在具有别名的字段上进行 ORDER BY

Question

我有如下查询

   SELECT
  final_avg_total.`Provider Name`,
  ROUND(SUM(final_avg_total.avg_total_payments), 2) AS avg_payments,
  ROUND(SUM(final_avg_total.avg_covered_charges), 2) AS avg_covered,
  (SUM(final_avg_total.avg_covered_charges) - SUM(final_avg_total.avg_total_payments)) / SUM(final_avg_total.avg_covered_charges) AS total_average,
  1 - (SUM(final_avg_total.avg_covered_charges) - SUM(final_avg_total.avg_total_payments))/SUM(final_avg_total.avg_covered_charges) AS total_percentage
FROM final_avg_total
GROUP BY final_avg_total.`Provider Id`
ORDER BY final_avg_total.`avg_payments`  DESC

我想在以下字段中使用别名 avg_payments 进行排序，但出现此错误。

 Unknown column avg_payments in the order by clause

Answer 1

avg_payments 不是表中的字段。只需删除表别名:

ORDER BY avg_payments  DESC

MySQL 理解 order by 语句中的列别名。