POSTGRES SQL QUERY错误，语法无效

Question

我有与此类似的查询

select to_char(
    select min(date) from MyTable, 
    'YYYY-MM-DD'
);

但是我一直收到此错误

ERROR:  syntax error at or near "select"
LINE 2:  select min(date) from MyTable, 
     ^
SQL state: 42601
Character: 18

Answer 1

子查询需要自己的括号：

select to_char( (select min(date) from MyTable), 'YYYY-MM-DD');

更传统的说法是：

select to_char(min(date), 'YYYY-MM-DD')
from MyTable;

不需要子查询。