一、between
It displays the value of a certain interval;
The SELECT * the FROM ` User ` the WHERE ID the BETWEEN . 1 the AND 4 ; // show ID . 1 ~ data between 4
Two, in
Displaying a plurality of values of an attribute;
The SELECT * the FROM ` User ` the WHERE id the IN ( 1 , 2 , 3 ); // id is displayed ( 1 , 2 , 3 ) data
三、like
Fuzzy query
The SELECT * the FROM ` the User ` the WHERE username the LIKE ' % r ' ; // query the user name people r at the end of the SELECT * the FROM ` the User ` the WHERE username the LIKE ' r% ' ; // query the user names of people at the beginning of r the SELECT * the FROM ` user ` the WHERE username the LIKE ' % r% ' ; // query containing the user name who is r % wildcard, is understood to complement the missing portion
Four, ASC: ascending order, default value DESC: descending
The SELECT * the FROM ` the User ` the ORDER BY id ASC ; // query id ascending order based on the SELECT * the FROM ` the User ` the ORDER BY id DESC ; // according to id DESC query the SELECT * the FROM ` the User ` the ORDER BY id ASC , username; // according to ascending id, user name in alphabetical order, the weight of the former than the latter, the weight is higher than the user name id
Five, five aggregate function (max () min () avg () count () sum ())
SELECT COUNT (IFNULL (id, 0 )) from Student; // query id field number, if null , use 0 instead of
六、GROUP BY
Query packet: the same data into a set.
The SELECT Sex, COUNT ( * ) the FROM ` the User ` the GROUP BY Sex; // grouped by gender, and the number of inquiries each group
七、having
Eight, limit
LIMIT is limiting sense, so LIMIT role is to limit the number of query records.
LIMIT offset,length;
offset : start line number, from 0 starts counting, and if omitted, the default is 0
length : number of rows returned, counted from the number of offset