Question

我的数据库中有一个表，可以保存多达60个字段，表示是或否。我想要COUNT或从表中的所有字段中获取SUM WHERE任何字段等于'yes';

我尝试过以下但没有运气：

SELECT count(*) FROM information_schema.columns WHERE table_name = 'portraits';

这将返回列数，但不允许我计算它们等于“是”的字段。

我想知道这在php中更容易吗？我目前在codeigniter中这样做，我不知道如何读取键/值，因为它是一个对象。有什么想法吗？

Answer 1

SELECT count(*) 
FROM information_schema.columns 
    WHERE table_name = 'portraits'
    AND (field1=0 OR field2=0 OR .... OR fieldN=0);

Answer 2

尝试这个....这个简单的查询将起作用..... :)

SELECT
SUM(IF( information_schema = "YES", 1, 0) AS Yes,
SUM(IF( information_schema != "YES", 1, 0) AS No, 
FROM portraits

Answer 3

试试这个：

SELECT state, count(*) FROM information_schema.columns GROUP BY state;

或者以更复杂的方式：

SELECT y.total, n.total
  FROM (SELECT count(*) as total FROM information_schema.columns WHERE table_name = 'portraits' AND state = 'yes') as y,
       (SELECT count(*) as total FROM information_schema.columns WHERE table_name = 'portraits' AND state = 'no') as n

MySql中字段的COUNT或SUM

3 个答案: