mysql - 从 select 内的子查询生成的别名字段

Question

我有一个像这样的选择查询:

SELECT 
emp_des_company as 'Company', 
(SELECT pav_des_valor FROM slt_pergunta_avaliacao pa, slt_avaliacao a WHERE pa.pav_idn_pergunta = 393 AND c.cas_idn_avaliacao = a.avl_idn_avaliacao)
FROM slt.case
...

我如何为这个子查询设置别名:

SELECT 
emp_des_company as 'Company', 
(SELECT pav_des_valor FROM slt_pergunta_avaliacao pa, slt_avaliacao a WHERE pa.pav_idn_pergunta = 393 AND c.cas_idn_avaliacao = a.avl_idn_avaliacao) as (SELECT per_des_descricao WHERE per_idn_pergunta = 393) 
FROM slt.case
...

提前致谢。

Answer 1

您不能简单地在静态 SQL 中使用动态值作为列别名。您必须使用固定值:AS column_name

一种替代方案是动态创建查询，请查看 prepared statements .