sql - 错误 : syntax error at or near "select"

Question

这段代码给了我一个ERROR: syntax error at or near "select"

SELECT name_one, name_two, jaro(
   select name from clients limit 50 as name_one, 
   select name from clients limit 50 as name_two
);

这很好用:

select jaro('aaa','aaa');

但是现在我需要从表中获取数据

Answer 1

以下是您可以为所有名称对选择 jaro(name1, name2) 的方法:

SELECT
    t1.name as name1
,   t2.name as name2
,   jaro(t1.name, t2.name) as jaro
FROM
   (select name from clients limit 50) t1
CROSS JOIN
    (select name from clients limit 50) t2

此查询使用所谓的 self cross join - 它从您的 clients 表中生成所有名称对。