Question

我有两张中继表：

Fields: ID(prim. key), Title
Values: ID(prim. key), Value, field_id(for. key)

简单来说，我有很多字段，而每个字段可以包含多个值。

我需要SQL查询来选择值不等于给定值的所有字段。

样品：

Assuming I have two fields:
- fld1 { 1,2,5 }
- fld2 { 1,4 }
I need to get fld1 while looking for fields whose value is NOT equal to 4.

Answer 1

这样的东西？还是我完全误解了你？

select *
  from Fields f
    inner join `Values` v
      on f.id = v.field_id
    where v.value <> 4;

Answer 2

SELECT title 
FROM `Fields` f
WHERE NOT EXISTS (SELECT 1 
                 FROM `Values` v
                 WHERE f.id = v.field_id 
                       AND v.`value` = 4);

SQL Fiddle

需要帮助构建SQL查询

2 个答案: