Question

说我有这样一张桌子：

CREATE TABLE item (
    id text NOT NULL,
    price integer NOT NULL,
    colors text[] DEFAULT ARRAY[]::text[],
    sizes text[] DEFAULT ARRAY[]::text[]
);

这样的数据：

INSERT INTO item VALUES ('1', 100, array['red', 'blue', 'green'], array['s', 'l']);
INSERT INTO item VALUES ('2', 5000, array['yellow', 'green'], array['s']);
INSERT INTO item VALUES ('3', 300, array['red'], array['s', 'l', 'xl']);
INSERT INTO item VALUES ('4', 150, array['white'], array['xxl']);

现在假设我有这个问题：

SELECT * from item WHERE price > 50 AND price < 400 AND colors&&ARRAY['red'] AND sizes&&ARRAY['s', 'l', 'xxl'] ORDER BY price OFFSET 0 LIMIT 10;

结果集是

 | id | price | colors             | sizes
1| 1  | 100   | {red, blue, green} | {s, l}
1| 3  | 300   | {red}              | {s, l, xl}

我的问题是：如何更改查询不仅返回此结果集，还返回此查询的所有可能大小（不包括任何大小条件，即排除sizes&&ARRAY['s', 'l', 'xxl']），此查询的所有可能颜色（仅排除颜色条件，即不包括colors&&ARRAY['red']）和价格范围，仅忽略查询中的价格条件（即排除price > 50 AND price < 400）？类似的东西：

 | id | price | colors             | sizes      | p_sizes    | p_colors                          | min_price | max_price |
1| 1  | 100   | {red, blue, green} | {s, l}     | {s, l, xl} | {'red', 'blue', 'green', 'white'} | 100       | 300       |
1| 3  | 300   | {red}              | {s, l, xl} | {s, l, xl} | {'red', 'blue', 'green', 'white'} | 100       | 300       |

其中p_colors是查询的不同颜色列表：

SELECT * from item WHERE price > 50 AND price < 400 AND sizes&&ARRAY['s', 'l', 'xxl'] ORDER BY price OFFSET 0 LIMIT 10;

 | id | price | colors             | sizes
1| 1  | 100   | {red, blue, green} | {s, l}
1| 4  | 150   | {white}            | {xxl}
1| 3  | 300   | {red}              | {s, l, xl}

p_sizes是查询的不同大小列表：

SELECT * from item WHERE price > 50 AND price < 400 AND colors&&ARRAY['red'] ORDER BY price OFFSET 0 LIMIT 10;

 | id | price | colors             | sizes
1| 1  | 100   | {red, blue, green} | {s, l}
1| 3  | 300   | {red}              | {s, l, xl}

min_price和max_price是查询的价格范围：

SELECT * from item WHERE colors&&ARRAY['red'] AND sizes&&ARRAY['s', 'l', 'xxl'] ORDER BY price OFFSET 0 LIMIT 10;
 | id | price | colors             | sizes
1| 1  | 100   | {red, blue, green} | {s, l}
1| 3  | 300   | {red}              | {s, l, xl}

-----编辑-----

添加了尺寸条件并将ID为2的项目的价格更改为5000以澄清问题。

Answer 1

此查询选择预期值：

select * 
from item,
lateral (
    select 
        array(select distinct unnest(colors) from item) all_colors,
        array(select distinct unnest(sizes) from item) all_sizes,
        min(price) min_price,
        max(price) max_price
    from item
) sub
where price > 50 and price < 400 AND colors&&ARRAY['red'] order by price;

 id | price |      colors      |  sizes   |          all_colors           |  all_sizes   | min_price | max_price 
----+-------+------------------+----------+-------------------------------+--------------+-----------+-----------
 1  |   100 | {red,blue,green} | {s,l}    | {yellow,blue,white,green,red} | {xl,s,l,xxl} |       100 |       300
 3  |   300 | {red}            | {s,l,xl} | {yellow,blue,white,green,red} | {xl,s,l,xxl} |       100 |       300
(2 rows)

您可以在横向联接中将查询结果与原始查询结合起来：

select * 
from item,
lateral (
    select array(
        select distinct unnest(colors) 
        from item 
        where price > 50 and price < 400) all_colors) q1,
lateral (
    select array(
        select distinct unnest(sizes) 
        from item
        where price > 50 and price < 400 and colors && ARRAY['red']) all_sizes) q2,
lateral (
    select
        min(price) min_price,
        max(price) max_price
    from item
    where colors&&ARRAY['red']
) q3
where price > 50 and price < 400 and colors&&ARRAY['red'] order by price;

 id | price |      colors      |  sizes   |          all_colors           | all_sizes | min_price | max_price 
----+-------+------------------+----------+-------------------------------+-----------+-----------+-----------
 1  |   100 | {red,blue,green} | {s,l}    | {yellow,white,green,red,blue} | {l,s,xl}  |       100 |       300
 3  |   300 | {red}            | {s,l,xl} | {yellow,white,green,red,blue} | {l,s,xl}  |       100 |       300
(2 rows)

您可以将聚合查询拆分为三个部分，以具有不同的where子句，例如：

    TabLayout tabLayout = .... (findview or code creation )
    /** get selected tab index */
    int selectedTabPosition = tabLayout.getSelectedTabPosition();
    /** get tab for selected index or if u want any other tab set desired index */
    TabLayout.Tab tabAt = tabLayout.getTabAt(selectedTabPosition);
    /** get view - but first u need set custom view on tabl via Tab.setCustomView(View) */
    View tabView = tabAt.getCustomView():

PostgreSQL - 返回查询结果和不同的可能值

1 个答案: