查询行9,000,000到10,000,000

Question

postgresql新手，我有一个10,000,000行的表，我一次查询数百万行

SELECT mmsi, report_timestamp, position_geom, ST_X(position_geom) AS Long,ST_Y(position_geom) AS Lat 
FROM reports4 
WHERE position_geom IS NOT NULL 
ORDER by report_timestamp ASC 
LIMIT 1000000 
OFFSET 8000000

当我尝试查询最后几百万行时，没有显示任何内容

SELECT mmsi, report_timestamp, position_geom, ST_X(position_geom) AS Long,ST_Y(position_geom) AS Lat 
FROM reports4 
WHERE position_geom IS NOT NULL 
ORDER by report_timestamp ASC 
LIMIT 1000000 
OFFSET 9000000

不确定如果我正确地进行查询，或者我忽略了某些事情。

Answer 1

该表可能包含10,000,000行，但这些行中有多少行WHERE position_geom IS NOT NULL？

你得到了什么：

SELECT count(*)
FROM reports4
WHERE position_geom IS NOT NULL;