Create a new index to improve query performance of three SQL simultaneously

Source: Internet
Author: User

Title

CREATE TABLE ' score ' (' id ' int (one) not null, ' StudentID ' int (one) not null, ' Subjectid ' int (one) not null, ' score ' int ( One) not NULL, PRIMARY KEY (' id ')) engine=innodb DEFAULT charset=utf8;--new Index to improve query performance of three SQL Alter TABLE ' score ' ADD IND EX ' score ' (' Score ', ' StudentID ', ' Subjectid ') EXPLAIN SELECT * from score WHERE score=100; EXPLAIN SELECT * FROM score WHERE studentid=5 and score=100; EXPLAIN SELECT * FROM score WHERE studentid=5 and subjectid=2 and score=100;

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This article is from the "Tech Blue" blog, so be sure to keep this source http://bstdn.blog.51cto.com/8667020/1918329

Create a new index to improve query performance of three SQL simultaneously

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