teradata - 选择 TOP 1000 + 自定义用户 ID

Question

除了自定义用户 ID 列表之外，我还想根据收入选择前 1000 个用户 ID（这些不属于前 1000 个）

换句话说，我希望在 1 个查询中使用以下查询：

SELECT TOP 1000 * FROM XX
ORDER BY REVENUE DESC

SELECT * FROM XX
WHERE USER_ID IN (CUSTOM_LIST)

Answer 1

您需要一个联合，但由于 Set-Select 中不允许使用 TOP，因此您必须将其嵌套在派生表中：

SELECT *
FROM
 (
   SELECT TOP 1000 * FROM XX
   ORDER BY REVENUE DESC
 ) as dt

 UNION
  -- UNION ALL is more efficient, but a user from the custom list who is 
  -- also in the top 1000 would be returned twice

SELECT * FROM XX
WHERE USER_ID IN (CUSTOM_LIST)