将两个sql select查询（在postgres中）与LIMIT语句组合 [英] Combine two sql select queries (in postgres) with LIMIT statement

问题描述

我有一个表，我想要一个查询，该查询返回创建的最后10条记录以及ID为x的记录。

I've got a table and I want a query that returns the last 10 records created plus the record who's id is x.

我正在尝试执行-

SELECT * FROM catalog_productimage
ORDER BY date_modified
LIMIT 10
UNION
SELECT * FROM catalog_productimage
WHERE id=5;

但是看起来我不能放 LIMIT 在 UNION 之前的位置。我尝试添加另一列并将其用于排序-

But it doesn't look like I can put LIMIT in there before UNION. I've tried adding another column and using it for sorting -

SELECT id, date_modified, IF(false, 1, 0) as priority FROM catalog_productimage
UNION
SELECT, id, date_modified, IF(true, 1, 0) as priority FROM catalog_productimage
WHERE id=5
ORDER BY priority, date_modified
LIMIT 10;

但我的进步不大。

推荐答案

只需检查一下是否可行：

Just checked that this will work:

(SELECT * FROM catalog_productimage
ORDER BY date_modified
LIMIT 10)
UNION
SELECT * FROM catalog_productimage
WHERE id=5;

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