syntax error at or near “union“

syntax error at or near “union“"/>

syntax error at or near “union“

postgreSQL 使用union时遇到了一个问题：

syntax error at or near "union"

1. 问题 sql 如下：

	select tech_model as model from dim_product_attribute_acc where tech_model is not null group by tech_model order by tech_modelunionselect 'N/A' as model

2. 原因

order by 的问题
order by 不能 和 union 同时使用
正解如下：

with tem as(select tech_model as model from dim_product_attribute_acc where tech_model is not null group by tech_model  order by tech_model
)
select model from tem 
union
select 'N/A' as model

把order 放到外层即可。