- how do I query the last 100 pieces of data in multiple tables in the ORACLE database? For example, the two tables of An and B have a time field, and the last 100 items of data in tables An and B are not the last 100 items in An and B.
--sqlserver
-- A B [Id][Time]
SELECT TOP 100 [Id],[Time] FROM
(
SELECT [Id],[Time] FROM [Table_A]
UNION ALL
SELECT [Id],[Time] FROM [Table_B]
) [NewTable_V]
ORDER BY [Time] DESC I don't know if SQL itself has any good methods, but we can work around it:
find the last 100 items of data in two tables, then these 100 items of data must be in the first 100 items of An and B.
is simple enough to find the first 100 pieces of data for An and B, and then sort them in the business logic.
use two tables union to combine the last hundred pieces of data to form a temporary table
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