Mysql-mysql basic operation commands

Mysql -- mysql basic operation command: selectDATE_FORMAT (runTime, % Y-% c-% d) fromhdfsPicLogtwherepathlike % liveEpg3 % andcount30andDATE_FORMAT (runTime, % Y-% c-% d) 2013-10-30; change the primary key to primary key auto-increment: altertablehdfsPicLogm

Mysql -- mysql basic operation command: select DATE_FORMAT (runTime, '% Y-% c-% D ') from hdfsPicLog t where path like '% liveEpg/3/%' and count 30 and DATE_FORMAT (runTime, '% Y-% c-% D') = '2017-10-30 '; change the primary key to primary key auto-increment: alter table hdfsPicLog m

Mysql-mysql basic operation commands

Date formatting usage:

Select DATE_FORMAT (runTime, '% Y-% c-% D') from hdfsPicLog t where path like' % liveEpg/3/% 'and count <30 and DATE_FORMAT (runTime, '% Y-% c-% D') = '2017-10-30 ';

Primary Key
Change to primary key auto-increment: alter table hdfsPicLog modify column hdfsId int unsigned not null auto_increment, add primary key (hdfsId );

Add a new column
Alter table t2 add d timestamp;
Alter table hdfsPicLog add channelId VARCHAR (255 );
Alter table infos add ex tinyint not null default '0 ';

Delete column
Alter table t2 drop column c;

Rename a column
Alter table t1 change a B integer;

Change column type
Alter table t1 change B bigint not null;
Alter table infos change list tinyint not null default '0 ';

Rename a table
Alter table t1 rename t2;

Add Index
Mysql> alter table tablename change depno int (5) not null;
Mysql> alter table tablename add index name (field name 1 [, field name 2…]);
Mysql> alter table tablename add index emp_name (name );

Index with primary keywords
Mysql> alter table tablename add primary key (id );

Add an index with unique conditions
Mysql> alter table tablename add unique emp_name2 (cardnumber );

Delete An index
Mysql> alter table tablename drop index emp_name;

Modify Table:
Add field:
Mysql> alter table table_name ADD field_name field_type;

Modify the original field name and type:
Mysql> alter table table_name CHANGE old_field_name new_field_name field_type;

Delete field:
Mysql> alter table table_name DROP field_name;

Sequence of moving columns in a table:
Forward: alter table hdfsPicLog modify hdfsId int first;
Backward: alter table user_info modify user_name varchar (10) after user_id;