sql - 在单个列上进行复杂选择

Question

我有这张 table

create table customers(id int, cust text, email id, cust_grp int);

我使用以下选择查询在 3 种不同的条件下获得 3 个结果

select count(*) as cust_with_email 
from customers where email<>'' and cust_grp=101;

result
--------
199

select count(*)  as cust_without_email  
from customers where email='' and cust_grp=101;
result
--------
3370

select count(*)  as cust_total 
from customers where  cust_grp=101;
result
--------
3569

但现在我需要将这三个查询组合成一个选择，预期的输出是:

 custemaildet
---------------------
3569|199|3370

Answer 1

您可以使用 case when过滤 email column 并使用 | 符号连接结果

SELECT count(*) || '|' || count(CASE 
            WHEN email <> ''
                THEN email
            END) || '|' || count(CASE 
            WHEN email = ''
                THEN email
            END) custemaildet
FROM customers 
WHERE cust_grp= 101