Mysql查询中不能使用AS

Question

    SELECT
employees.emp_id,
employees.emp_name_en,
employees.emp_name_ar,
employees.emp_nike_name,
employees.emp_basic_salary,
employees.emp_aw_food,
employees.emp_aw_car,
employees.emp_aw_mobile,
employees.emp_aw_trans,
employees.emp_aw_housing,

((`settings`.`set_value` * `employees`.`emp_basic_salary`) / 100) AS insurance_ratio,
(((((`employees`.`emp_aw_housing` + `employees`.`emp_aw_trans`) + `employees`.`emp_aw_mobile`) + `employees`.`emp_aw_car`) + `employees`.`emp_aw_food`) + `employees`.`emp_basic_salary`) - ((`settings`.`set_value` * `employees`.`emp_basic_salary`) / 100)  AS net_salary,
  (net_salary / 30 ) AS day_salary
FROM
employees ,
settings
WHERE
settings.set_key =  'insurance_ratio'

[Err] 1054 - “字段列表”中的未知列“net_salary”

我如何使用“net_salary”列

Answer 1

但是你能做什么...

SELECT tab1.*, (tab1.net_salary / 30 ) AS day_salary 
FROM (SELECT
employees.emp_id,
employees.emp_name_en,
employees.emp_name_ar,
employees.emp_nike_name,
employees.emp_basic_salary,
employees.emp_aw_food,
employees.emp_aw_car,
employees.emp_aw_mobile,
employees.emp_aw_trans,
employees.emp_aw_housing,

((`settings`.`set_value` * `employees`.`emp_basic_salary`) / 100) AS insurance_ratio,
(((((`employees`.`emp_aw_housing` + `employees`.`emp_aw_trans`) + `employees`.`emp_aw_mobile`) + `employees`.`emp_aw_car`) + `employees`.`emp_aw_food`) + `employees`.`emp_basic_salary`) - ((`settings`.`set_value` * `employees`.`emp_basic_salary`) / 100)  AS net_salary
FROM
employees ,
settings
WHERE
settings.set_key =  'insurance_ratio') AS tab1