查询链接：
http://dev.mysql.com/doc/refman/5.7/en/func-op-summary-ref.htmlhttp://www.w3resource.com/mysql/mysql-functions-and-operators.php
http://www.tutorialspoint.com/mysql/mysql-date-time-functions.htm
1.SELECT FROM WHERE
SELECT user_guid, free_start_user FROM users WHERE free_start_user=1;2.OPERATORS
/* If you wanted to examine the Dog IDs of dogs who weighed between 10 and 50 pounds, you could query: */ SELECT dog_guid, weight FROM dogs WHERE weight BETWEEN 10 AND 50; SELECT dog_guid, dog_fixed, dna_tested FROM dogs WHERE dog_fixed=1 OR dna_tested=1;SELECT dog_guid, dog_fixed, dna_tested FROM dogs WHERE dog_fixed=1 AND dna_tested!=1;
3.字符串的使用需要加引号。
双引号或者单引号，单包含关键字的必须是 ``号。
SELECT dog_guid, breed FROM dogs WHERE breed='golden retriever';/* The IN operator allows you to specify multiple values in a WHERE clause. */ SELECT dog_guid, breed FROM dogs WHERE breed IN ("golden retriever","poodle");
LIKE 操作符。
SELECT dog_guid, breed FROM dogs WHERE breed LIKE ("s%"); /* WHERE breed LIKE ("s%") = the breed must start with "s", but can have any number of letters after the "s" WHERE breed LIKE ("%s") = the breed must end with "s", but can have any number of letters before the "s" WHERE breed LIKE ("%s%") = the breed must contain an "s" somewhere in its name, but can have any number of letters before or after the "s */4.时间操作符
/* DATE - format YYYY-MM-DD DATETIME - format: YYYY-MM-DD HH:MI:SS TIMESTAMP - format: YYYY-MM-DD HH:MI:SS YEAR - format YYYY or YY */SELECT dog_guid, created_at FROM complete_tests WHERE DAYNAME(created_at)="Tuesday" /******************************/ SELECT dog_guid, created_at FROM complete_tests WHERE DAY(created_at) > 15 /***************************/ SELECT dog_guid, created_at FROM complete_tests WHERE created_at > '2014-02-04' SELECT dog_guid, test_name, subcategory_name FROM complete_tests WHERE YEAR(created_at) = '2014' and MONTH(created_at)='10'
5.判断是否为NULL。
SELECT user_guid FROM users WHERE free_start_user IS NOT NULL; /*****************************/ SELECT user_guid FROM users WHERE free_start_user IS NULL;
转载于:https://www.cnblogs.com/Shinered/p/9501787.html
