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This article introduces the relevant knowledge of "what is the method of SQL optimizing limit pagination". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

The problem with Limit and OFFSET is actually the problem with OFFSET, which causes MySQL to scan a large number of unwanted lines and then throw them away. If you use bookmarks, you can record the location of the previously fetched data. Then next time, you can start the scan directly from the recorded location.

Let's look at a case study:

Mysql > select id,product_id from product order by id desc limit 20 +-+-+ | id | product_id | +-+- -- + | 71986 | 63308c71b16642a4bfb75cbe1049188b | | 71985 | bb8eba635b6a4726b4172143fb1c1d04 | | 71984 | 273243e1c9c64ee39351ea01a2489fa6 | | 71983 | 83f253b3ecde47eebe6a6397dc0d319e | | 71982 | 3c9780c86d1f4f24b95c9a08b4839c99 | | 71981 | 183b197924434de0a47d1786773cb66f | | 71980 | aff3b1385ee74893a3729664991d8e86 | | 71979 | c662a0e5c4d64339a5a68b99268840e1 | | 71978 | fe905e3dbdd2421c8e5ca47cd47232a4 | | 71977 | 9a44f05fde72425fa4498b091d27fd58 | | 71976 | c31afbd9c4ac46ffac34b2a14a49fb9f | | 71975 | 62056557531143e18bc813c0c930dc96 | | 71974 | 4ea1f0c978ca4441a232f563ba7181ee | | 71973 | 413317481ccf449394ded39b53a0f5cf | 71972 | 493c6da548394bdc871d058bc93a9b93 | 71971 | 98fafa3c690243998b18da8a9f165297 | | 71970 | 2e299b3ad38d4ce48bd1481799cb11a2 | | 71969 | 7f176c93d9ac42659b40a40f4fbea937 | | 71968 | d87671838a3246ddb393a336b8806905 | | 71967 | 301e3b9cb8ab40d588547a9b7f8fdaba | +-+-+

In reverse id order, the first page takes 20 lines, and the id ranges from 71967 to 71986.

Next page:

Mysql > select id,product_id from product where id < 71967 order by id desc limit 20 +-+-+ | id | product_id | +-+- -- + | 71966 | fec841328f76466098e0f7ff71ad2e64 | | 71965 | 91383bdf53f64c0c957f00f5e894ee08 | | 71964 | 0fe1f36aecc64e59b1f833e2a809b1d9 | | 71963 | 583ccc4dd2bc48889b672c700ff723df | | 71962 | 2d7417d85f7d4bc5a403be95d42c66c2 | | 71961 | f46e02c1abc046ffba6a893a0af32211 | | 71956 | 1acd9bf330d24cfd90005cc2ade28f8d | | 71959 | cea963ee97814bc09b657c0453b0cb55 | | 71958 | 700caf0dc6c745198d141c8006f87ee3 | | 71957 | 2239be33ebd2485ea6209b5186456531 | | 71956 | 30a4095734074612ad0a0fb32bdab1e4 | | 71955 | d9071a755a994f2eae11c9fb17e8071a | | 71954 | 4d0453c47af347078bc6bc2b5942061c | | 71953 | dda45cced0844fd992194cbaa334e420 | 71952 | 6e65d866889e4b15abe272f1e814ecc2 | 71951 | 4b22cdbb1f34448494251fd4f3eb6425 | | 71950 | 38f5d0cac07a4dc5a33ca62609a6debd | | 71949 | faa53f03f4714c9bb0991eb6b18ed7d9 | | 71948 | c5719ee4fcad48d0a6bfc8f28b415f1e | | 71947 | c6beaaa94829465ab1f9b6e0187d2721 | +-+-+

This ensures that each paging query is efficient, but there are certain conditions for using such a query, such as:

1. There must be a primary key and it is monotonously increasing.

2. If the query statement has group by grouping, then this method cannot be used.

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