Database operation--query

A \g

Effect: Changes the display of the output results so that the output is displayed as columns.

Note: \g is uppercase, the SQL statement is not delimited after using the \g parameter;. If added, the error will be reported:

 from mysql.user \g*************************** 1. Row ***************************                  host:localhost                  user:root              *  23ae809ddacaf96af0fd78ed04b6a265e05aa257           select_priv:y           insert_priv:y           update_priv:y           Delete_ Priv:y           create_priv:y             drop_priv:y           reload_priv:y         shutdown_priv:y          process_priv:y

Ps:

　　

 from Mysql.user \g; 1. Row ***************************                  host:localhost                  user:root              *  23ae809ddacaf96af0fd78ed04b6a265e05aa257           select_priv:y           insert_priv:y           update_priv:y           Delete_ Priv:y           create_priv:y             drop_priv:y           reload_priv:y         shutdown_priv:y          process_priv:y             File_priv:y            grant_priv:y       references_priv:y            index_priv:y            alter_priv:y          show_db_priv:y            super_priv:y create_tmp_table_priv:y

Error:no query specified

Two Insert Table

Comparison of the two operations:

Create operation, table does not exist previously

mysql> CREATE TABLE t1 (x char), y char (+)) Select Host,user fromMysql.user; Query OK,Rows affected (0.57sec) Records:11duplicates:0 Warnings:0mysql> CREATE TABLE t2 (host char, user char ()) Select Host,user fromMysql.user; Query OK,Rows affected (0.58sec) Records:11duplicates:0 Warnings:0mysql>desc T1;+-------+----------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+-------+----------+------+-----+---------+-------+| x | char (60) |     YES | |       NULL | || y | char (16) |     YES | |       NULL | || Host | char (60) |     NO |         |       | || user | char (16) |     NO |         |       | |+-------+----------+------+-----+---------+-------+4 rowsinchSet (0.01sec) MySQL>desc T2;+-------+----------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+-------+----------+------+-----+---------+-------+| Host | char (60) |     YES | |       NULL | || user | char (16) |     YES | |       NULL | |+-------+----------+------+-----+---------+-------+2 rowsinchSet (0.01 sec)

mysql> CREATE TABLE t1 (id int, name char (10)); Query OK, 0 rows affected (0.30sec) MySQL> CREATE TABLE t2 (id int, name char (10)); Query OK, 0 rows affected (0.29sec) MySQL>Insert T2 Values(1,'Alex'),    (2,'Egon'); Query OK,2 rows affected (0.29sec) Records:2duplicates:0 Warnings:0mysql>Insert T1 Values(1,'Wupeiqi'); Query OK,1 row affected (0.30sec) MySQL> Insert T1 Select id,name fromT2; Query OK,2 rows affected (0.32sec) Records:2duplicates:0 Warnings:0mysql> select * fromT1;+------+---------+| ID |    Name |+------+---------+| 1 |    Wupeiqi | | 1 |    Alex | | 2 | Egon |+------+---------+3 rowsinchSet (0.00 sec)

Select as Usage

From onerows affected (0.57  duplicates:0  warnings:0mysqlfrom  T1; +--------------+-----------+| Host Address     | user name    |+--------------+-----------+|%            | Alex      | |%            | Egon      | |%            | egon1     | |%            | Yuanhao   | |  %            | Zuo       | |%            | zuo1      | | 127.0.0.1    | root      | |:: 1          | root |      | localhost    |           | | localhost |    root      | | localhost    | zuo in        Set (0.00 sec)

Insert action table previously exists

mysql> CREATE TABLE t1 (id int, name char (10)); Query OK, 0 rows affected (0.30sec) MySQL> CREATE TABLE t2 (id int, name char (10)); Query OK, 0 rows affected (0.29sec) MySQL>Insert T2 Values(1,'Alex'),    (2,'Egon'); Query OK,2 rows affected (0.29sec) Records:2duplicates:0 Warnings:0mysql>Insert T1 Values(1,'Wupeiqi'); Query OK,1 row affected (0.30sec) MySQL> Insert T1 Select id,name fromT2; Query OK,2 rows affected (0.32sec) Records:2duplicates:0 Warnings:0mysql> select * fromT1;+------+---------+| ID |    Name |+------+---------+| 1 |    Wupeiqi | | 1 |    Alex | | 2 | Egon |+------+---------+3 rowsinchSet (0.00 sec)

Database operation--query