Question

以下面的格式提供我的访问表。

ID  access value
1   18      ab
1   32      bc
1   48      cd
2   18      ef
3   18      ab  
3   32      bc

我需要根据输入获取所有可以访问某些号码的ID。

如果输入为[{access:18,value:ab},{access:32, value:bc}]

select id from access where access = 18 and value ='ab'
intersect
select id from access where access = 32 and value = 'bc'

输出为1,3

如果输入为[{access:18,value:ab},{access:32, value:bc},{access:48,value:cd}]

select id from access where access = 18 and value ='ab'
intersect
select id from access where access = 32 and value ='bc'
intersect
select id from access where access = 48 and value ='cd'

输出为1.

如何以更好的方式编写上述查询，以便根据输入我可以实现所需的结果。

Answer 1

你的方法很好。另一种方法是：

<form id="comment_form" action="{%  url 'operation:update_comment'%}" method="POST" >
{% csrf_token %}

<textarea id="js-pl-textarea"name="comment"></textarea>

<input type="submit" value="Submit"> </input>

</form>

Answer 2

我认为您将输入作为json数组传递。您可以使用json_to_recordset将其转换为行，然后使用access表格进行联接，并将计数与HAVING进行比较以获得交集。

SQL Fiddle

PostgreSQL 9.6架构设置：

CREATE TABLE access
    (ID int, access int, value varchar(2))
;

INSERT INTO access
    (ID, access, value)
VALUES
    (1, 18, 'ab'),
    (1, 32, 'bc'),
    (1, 48, 'cd'),
    (2, 18, 'ef'),
    (3, 18, 'ab'),
    (3, 32, 'bc')
;

查询1 ：

SELECT  ID
FROM access a
INNER JOIN (
    SELECT *, COUNT(*) OVER () as ct
    FROM json_to_recordset('[{"access":18,"value":"ab"},{"access":32, "value":"bc"}
                            ,{"access":48,"value":"cd"}
                            ]'
                          ) 
        AS j("access" INT, "value" TEXT)
    ) j ON (
        j.access = a.access
        AND j.value = a.value
        ) GROUP BY ID HAVING COUNT(*) = MAX(ct)

<强> Results ：

| id |
|----|
|  1 |

在同一个表上动态交叉选择查询

2 个答案: