设置:
CREATE TABLE tbl (group_id integer, id integer)
INSERT INTO tbl VALUES (1, 1)
INSERT INTO tbl VALUES (1, 2)
INSERT INTO tbl VALUES (1, 3)
INSERT INTO tbl VALUES (2, 1)
INSERT INTO tbl VALUES (2, 2)
INSERT INTO tbl VALUES (3, 1)
...
INSERT INTO tbl VALUES (999, 999999)
查询#1
SELECT * FROM tbl WHERE group_id > 1 AND group_id < 10 AND id > 100
查询#2
SELECT * FROM tbl WHERE id > 100 AND group_id > 1 AND group_id < 10
查询#1和查询#2之间是否存在性能差异?
更具体地说,在查询“较高分辨率”列(例如id
)之前查询“较低分辨率”列(例如group_id
)有什么优点或缺点?
(使用Postgresql)
https://stackoverflow.com/questions/56466597
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