算例时 * [英] Count case when *

问题描述

我在 count case 语句中遇到错误，我希望能得到一些帮助.

I am getting an error in my count case statement and I was hoping I could get some help.

我的代码行是

count(case when product = 'classic' then * end)

我得到的错误信息是

错误:*"处或附近的语法错误第 4 行:...t(case when initial_product_line = 'classic' then * end) as ...

ERROR: syntax error at or near "*" LINE 4: ...t(case when initial_product_line = 'classic' then * end) as ...

我不能数数吗*?^

推荐答案

* 在 SQL 中有特殊含义，你需要 1 或columnname 代替:

* has special meaning in SQL, you need either 1 or columnname instead :

count(case when product = 'classic' then col end)

您也可以将其简化为:

sum(case when product = 'classic' then 1 else 0 end)

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