sql教程8 NULL ALTER DROP RENAME LIMIT
SQL SELECT语法
SELECT [DISTINCT|ALL ] { * | [fieldExpression [AS newName]} FROM tableName [alias] [WHERE condition][GROUP BY fieldName(s)] [HAVING condition] ORDER BY fieldName(s)
mysql> SELECT Concat(`title`, ' (', `director`, ')') , `year_released` FROM `movies`;+---------------------------------------------+---------------+| Concat(`title`, ' (', `director`, ')') | year_released |+---------------------------------------------+---------------+| Pirates of the Caribean 4 ( Rob Marshall) | 2011 || Forgetting Sarah Marshal (Nicholas Stoller) | 2008 || NULL | 2008 || Code Name Black (Edgar Jimz) | 2010 || NULL | 2007 || NULL | 2007 || NULL | 2007 || Honey mooners (John Schultz) | 2005 || NULL | 2012 || The Great Dictator (Chalie Chaplie) | 1920 || movie 3 (John Brown) | 1920 |+---------------------------------------------+---------------+11 rows in set (0.04 sec)mysql> SELECT Concat(`title`, ' (', `director`, ')') AS 'Concat', `year_released` FROM `movies`;+---------------------------------------------+---------------+| Concat | year_released |+---------------------------------------------+---------------+| Pirates of the Caribean 4 ( Rob Marshall) | 2011 || Forgetting Sarah Marshal (Nicholas Stoller) | 2008 || NULL | 2008 || Code Name Black (Edgar Jimz) | 2010 || NULL | 2007 || NULL | 2007 || NULL | 2007 || Honey mooners (John Schultz) | 2005 || NULL | 2012 || The Great Dictator (Chalie Chaplie) | 1920 || movie 3 (John Brown) | 1920 |+---------------------------------------------+---------------+11 rows in set (0.00 sec)mysql> SELECT `membership_number`,`full_names`,LEFT(`date_of_birth`,4) AS `year_of_birth` FROM members;+-------------------+---------------------+---------------+| membership_number | full_names | year_of_birth |+-------------------+---------------------+---------------+| 1 | Janet Jones | 1980 || 2 | Janet Smith Jones | 1980 || 3 | Robert Phil | 1989 || 4 | Gloria Williams | 1984 || 5 | Leonard Hofstadter | NULL || 6 | Sheldon Cooper | NULL || 7 | Rajesh Koothrappali | NULL || 8 | Leslie Winkle | 1984 || 9 | Howard Wolowitz | 1981 |+-------------------+---------------------+---------------+9 rows in set (0.00 sec)mysql> SELECT * FROM members WHERE membership_number IN (1,2,3);+-------------------+-------------------+--------+---------------+------------------------+----------------+----------------+---------------------+| membership_number | full_names | gender | date_of_birth | physical_address | postal_address | contact_number | email |+-------------------+-------------------+--------+---------------+------------------------+----------------+----------------+---------------------+| 1 | Janet Jones | Female | 1980-07-21 | First Street Plot No 4 | Private Bag | 0759 253 543 | janetjones@yagoo.cm || 2 | Janet Smith Jones | Female | 1980-06-23 | Melrose 123 | NULL | NULL | jj@fstreet.com || 3 | Robert Phil | Male | 1989-07-12 | 3rd Street 34 | NULL | 12345 | rm@tstreet.com |+-------------------+-------------------+--------+---------------+------------------------+----------------+----------------+---------------------+3 rows in set (0.03 sec)

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