SHOW AUTHORS
顾名思义，这个要展示的是各位MYSQL开发者的信息，包括姓名，住址及相关注解
e.g.1
mysql> show authors\G;
*************************** 1. row
***************************
Name: Brian
(Krow) Aker
Location: Seattle, WA, USA
Comment:
Architecture, archive, federated, bunch of little stuff :)
*************************** 2. row
***************************
Name: Venu
Anuganti
Location:
Comment:
Client/server protocol (4.1)
SHOW BINARY LOGS
SHOW MASTER LOGS
显示server上的二进制日志文件，其中BINARY==MASTER.
e.g.1
mysql> show binary logs;
+-------------------+-----------+
| Log_name| File_size |
+-------------------+-----------+
| mysqld-bin.000001 |125 |
| mysqld-bin.000002 |125 |
| mysqld-bin.000003 |50481050 |
| mysqld-bin.000004 |125 |
| mysqld-bin.000005 |125 |
| mysqld-bin.000006 |106 |
+-------------------+-----------+
6 rows in set (0.02 sec)
e.g.2
mysql> show master logs;
+-------------------+-----------+
| Log_name| File_size |
+-------------------+-----------+
| mysqld-bin.000001 |125 |
| mysqld-bin.000002 |125 |
| mysqld-bin.000003 |50481050 |
| mysqld-bin.000004 |125 |
| mysqld-bin.000005 |125 |
| mysqld-bin.000006 |106 |
+-------------------+-----------+
6 rows in set (0.00 sec)
SHOW BINLOG EVENTS
[IN 'log_name'] [FROMpos] [LIMIT [offset,]row_count]
显示二进制文件的相关信息。如果未指定日志文件名，则默认展示第一个二进制文件相关信息；其中LIMIT语法同SELECT.
e.g.1
mysql> show binlog events in 'mysqld-bin.000002'\G;
*************************** 1. row
***************************
Log_name:
mysqld-bin.000002
Pos: 4
Event_type:
Format_desc
Server_id: 1
End_log_pos: 106
Info: Server
ver: 5.1.52-log, Binlog ver: 4
*************************** 2. row ***************************
Log_name:
mysqld-bin.000002
Pos: 106
Event_type: Stop
Server_id: 1
End_log_pos: 125
Info:
2 rows in set (0.00 sec)
SHOW CHARACTER SET
[LIKE 'pattern' | WHEREexpr]
show character set显示MYSQL中的所有字符集信息。可用LIKE或WHERE子句进行过滤。如show character set like ‘u%’,列出所有以u开头的字符集.
e.g.1
mysql> show character set like 'u%';
+---------+-----------------+-------------------+--------+
| Charset | Description| Default collation | Maxlen |
+---------+-----------------+-------------------+--------+
| ujis| EUC-JP
Japanese | ujis_japanese_ci|3 |
| utf8| UTF-8
Unicode| utf8_general_ci|3 |
| ucs2| UCS-2
Unicode| ucs2_general_ci|2 |
+---------+-----------------+-------------------+--------+
3 rows in set (0.07 sec)
SHOW COLLATION
[LIKE 'pattern' | WHEREexpr]
show collation显示所有的排序规则。可用LIKE或WHERE子句进行过滤。如show collation like ‘u%’,列出所有以u开头的排序规则.
e.g.1
mysql> show collation like 'latin1%';
+-------------------+---------+----+---------+----------+---------+
| Collation| Charset | Id | Default | Compiled | Sortlen |
+-------------------+---------+----+---------+----------+---------+
| latin1_german1_ci | latin1|5
|| Yes|1 |
| latin1_swedish_ci | latin1|8 |
Yes| Yes|1 |
| latin1_danish_ci| latin1| 15 || Yes|1 |
| latin1_german2_ci | latin1| 31 || Yes|2 |
| latin1_bin| latin1| 47 || Yes|1 |
| latin1_general_ci | latin1| 48 || Yes|1 |
| latin1_general_cs | latin1| 49 || Yes|1 |
| latin1_spanish_ci | latin1| 94 || Yes|1 |
+-------------------+---------+----+---------+----------+---------+
8 rows in set (0.00 sec)
SHOW [FULL]
COLUMNS {FROM | IN}tbl_name[{FROM | IN}db_name]
[LIKE 'pattern' | WHEREexpr]
显示某个数据库的某张表的列的信息，可通过like或where子句过虑。from
tbl_naem in db_name可用db_name.tbl_name替代。
e.g.1
mysql> show columns from admin_user in rec_bak like
'u%';
+------------+-------------+------+-----+---------+----------------+
| Field|
Type| Null | Key | Default |
Extra|
+------------+-------------+------+-----+---------+----------------+
| user_id|
smallint(5) | NO| PRI | NULL| auto_increment |
| user_code|
varchar(20) | NO||||
| user_name|
varchar(50) | NO||||
| user_name2 | varchar(30) | YES||
NULL||
+------------+-------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
SHOW CONTRIBUTORS
很显然
e.g.1
mysql> show contributors\G;
*************************** 1. row
***************************
Name: Ronald
Bradford
Location: Brisbane, Australia
Comment: EFF
contribution for UC2006 Auction
*************************** 2. row
***************************
Name: Sheeri
Kritzer
Location: Boston, Mass. USA
Comment: EFF
contribution for UC2006 Auction
*************************** 3. row
***************************
Name: Mark
Shuttleworth
Location: London, UK.
Comment: EFF
contribution for UC2006 Auction
3 rows in set (0.00 sec)
SHOW CREATE
{DATABASE | SCHEMA}db_name
e.g.1
mysql> show create database mysql\G;
*************************** 1. row
***************************
Database:
mysql
Create Database: CREATE DATABASE `mysql` /*!40100 DEFAULT
CHARACTER SET latin1 */
1 row in set (0.00 sec)
SHOW CREATE EVENTevent_name
显示指定event的create event语句.
SHOW CREATE
FUNCTIONfunc_name
显示指定func_name的create
function语句.
SHOW CREATE
PROCEDUREproc_name
显示指定proc_name的create
procedure语句.
SHOW CREATE TABLEtbl_name
显示指定tal_name的create table语句.
SHOW CREATE
TRIGGERtrigger_name
显示指定trigger_name的create
trigger语句.
SHOW CREATE VIEWview_name
显示指定view_name的create view语句.
e.g.1
mysql> show create view v_test\G;
*************************** 1. row
***************************
View: v_test
Create
View: CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY
DEFINER VIEW `v_test` AS select `b`.`barcode` AS `barcode`,`g`.`goods_sn` AS
`goods_sn`,`g`.`goods_name` AS `goods_name`,`c`.`color_code` AS
`color_code`,`c`.`color_name` AS `color_name`,`s`.`size_code` AS
`size_code`,`s`.`size_name` AS `size_name` from (((`goods_barcode` `b` join
`goods` `g` on((`b`.`goods_id` = `g`.`goods_id`))) join `color` `c`
on((`b`.`color_id` = `c`.`color_id`))) join `size` `s` on((`b`.`size_id` =
`s`.`size_id`)))
character_set_client: utf8
collation_connection: utf8_general_ci
1 row in set (0.00 sec)
SHOW {DATABASES |
SCHEMAS}
[LIKE 'pattern' | WHEREexpr]
show databases显示server上所有的数据库信息，可用like或where子句过虑；其中databases==schmas.
e.g.1
mysql> show databases like 'r%';
+---------------+
| Database (r%) |
+---------------+
| rec_bak|
+---------------+
1 row in set (0.00 sec)
SHOW ENGINEengine_name{STATUS | MUTEX}
显示相关存储引擎的一些操作信息.
e.g.1
mysql> show engine innodb status\G;
*************************** 1. row ***************************
Type: InnoDB
Name:
Status:
=====================================
110817 20:15:59 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 18 seconds
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 120, signal count
120
Mutex spin waits 0, rounds 1220, OS waits 61
RW-shared spins 6, OS waits 3; RW-excl spins 56, OS waits
56
------------
TRANSACTIONS
------------
Trx id counter 0 3072
Purge done for trx's n:o < 0 0 undo n:o < 0 0
History list length 0
LIST OF TRANSACTIONS FOR EACH SESSION:
……………………………………………………………………………………..
SHOW [STORAGE] ENGINES
显示server上存储引擎的状态信息
e.g.1
mysql> show storage engines\G;
*************************** 1. row
***************************
Engine:
MRG_MYISAM
Support: YES
Comment:
Collection of identical MyISAM tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 2. row
***************************
Engine: CSV
Support: YES
Comment: CSV storage
engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 3. row
***************************
Engine:
MyISAM
Support:
DEFAULT
Comment:
Default engine as of MySQL 3.23 with great performance
Transactions: NO
XA: NO
Savepoints: NO
*************************** 4. row
***************************
Engine:
InnoDB
Support: YES
Comment:
Supports transactions, row-level locking, and foreign keys
Transactions: YES
XA: YES
Savepoints: YES
*************************** 5. row
***************************
Engine:
MEMORY
Support: YES
Comment: Hash
based, stored in memory, useful for temporary tables
Transactions: NO
XA: NO
Savepoints: NO
5 rows in set (0.00 sec)
SHOW ERRORS [LIMIT
[offset,]row_count]
SHOW COUNT(*)
ERRORS
显示错误信息
统计错误信息数量
e.g.1
mysql> show errors;
Empty set (0.00 sec)
mysql> show count(*) errors;
+-----------------------+
| @@session.error_count |
+-----------------------+
|0 |
+-----------------------+
1 row in set (0.02 sec)
SHOW EVENTS [{FROM
| IN}schema_name]
[LIKE 'pattern' | WHEREexpr]
列出schema_name模式下，所有满足like或where条件的事件；
Show events；列出当前模式下的所有事件.
e.g.1
mysql> show events from rec_bak;
Empty set (0.03 sec)
SHOW FUNCTION CODEfunc_name
显示存储函数func_name的code
SHOW FUNCTION
STATUS
[LIKE 'pattern' | WHEREexpr]
显示(满足like或where条件的)存储函数的状态信息
e.g.1
mysql> show function status like 'p_%';
Empty set (0.00 sec)
SHOW GRANTS [FORuser]
e.g.1
mysql> SHOW GRANTS
FOR 'root'@'localhost';
+---------------------------------------------------------------------+
| Grants for root@localhost|
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH
GRANT OPTION |
+---------------------------------------------------------------------+
SHOW {INDEX |
INDEXES | KEYS}
{FROM | IN}tbl_name
[{FROM | IN}db_name]
[WHEREexpr]
e.g.1
mysql> show
index from huojia in rec_bak\G;
*************************** 1. row
***************************
Table:
huojia
Non_unique: 0
Key_name:
PRIMARY
Seq_in_index: 1
Column_name: hj_id
Collation: A
Cardinality: 1205
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
1 row in set (0.00 sec)
e.g.2
mysql> show keys from rec_bak.huojia\G;
*************************** 1. row
***************************
Table:
huojia
Non_unique: 0
Key_name:
PRIMARY
Seq_in_index: 1
Column_name: hj_id
Collation: A
Cardinality: 1205
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
1 row in set (0.00 sec)
e.g.3
mysql> show keys from goods in rec_bak\G;
*************************** 1. row ***************************
Table: goods
Non_unique: 0
Key_name:
PRIMARY
Seq_in_index: 1
Column_name:
goods_id
Collation: A
Cardinality: 18085
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
*************************** 2. row
***************************
Table: goods
Non_unique: 1
Key_name:
goods_sn
Seq_in_index: 1
Column_name:
goods_sn
Collation: A
Cardinality: 18085
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
……………………………………………………………………………………………………………………………………………………………………
*************************** 11. row
***************************
Table: goods
Non_unique: 1
Key_name:
ghs_id
Seq_in_index: 1
Column_name:
ghs_id
Collation: A
Cardinality: 2
Sub_part: NULL
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
11 rows in set (0.36 sec)
SHOW INNODB STATUS
==show engine innodb status
SHOW MASTER STATUS
显示主机(相对于slave)的bin-log
mysql> show master status;
+-------------------+----------+--------------+------------------+
| File| Position | Binlog_Do_DB | Binlog_Ignore_DB |
+-------------------+----------+--------------+------------------+
| mysqld-bin.000006 |106 |||
+-------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
SHOW OPEN TABLES [{FROM | IN}db_name]
[LIKE 'pattern' | WHEREexpr]
显示在表缓存中打开的，非临时表的信息
mysql> show open tables in mysql;
+----------+--------------+--------+-------------+
| Database | Table| In_use | Name_locked |
+----------+--------------+--------+-------------+
| mysql|
servers|0 |0 |
| mysql|
db|0 |0 |
| mysql|
host|0 |0 |
| mysql|
columns_priv |0 |0 |
| mysql|
user|0 |0 |
| mysql|
event|0 |0 |
| mysql|
tables_priv|0 |0 |
| mysql|
procs_priv|0 |0 |
+----------+--------------+--------+-------------+
SHOW PLUGINS
显示server插件信息
mysql> show plugins;
+------------+--------+----------------+---------+---------+
| Name|
Status | Type| Library |
License |
+------------+--------+----------------+---------+---------+
| binlog|
ACTIVE | STORAGE ENGINE | NULL|
GPL|
| partition|
ACTIVE | STORAGE ENGINE | NULL|
GPL|
| CSV|
ACTIVE | STORAGE ENGINE | NULL|
GPL|
| MEMORY| ACTIVE | STORAGE ENGINE | NULL| GPL|
| InnoDB|
ACTIVE | STORAGE ENGINE | NULL|
GPL|
| MyISAM|
ACTIVE | STORAGE ENGINE | NULL|
GPL|
| MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL| GPL|
+------------+--------+----------------+---------+---------+
7 rows in set (0.01 sec)
SHOW PRIVILEGES
显示MYSQL SERVER支持的所有系统权限
mysql> show privileges\G;
*************************** 1. row
***************************
Privilege: Alter
Context: Tables
Comment: To alter
the table
*************************** 2. row
***************************
Privilege: Alter routine
Context:
Functions,Procedures
Comment: To alter
or drop stored functions/procedures
*************************** 3. row
***************************
Privilege: Create
Context:
Databases,Tables,Indexes
Comment: To
create new databases and tables
SHOW PROCEDURE CODEproc_name
该语句仅能在支持debugging扩展的server上执行。它展示的是一个内部实现的命名存储过程。
mysql> DELIMITER //
mysql> CREATE PROCEDURE p1 ()
-> BEGIN
->DECLARE fanta INT DEFAULT 55;
->DROP TABLE t2;
->LOOP
->INSERT INTO t3 VALUES (fanta);
->END LOOP;
->END//
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW PROCEDURE CODE p1//
+-----+----------------------------------------+
| Pos | Instruction|
+-----+----------------------------------------+
|0 | set fanta@0
55|
|1 | stmt 9
"DROP TABLE t2"|
|2 | stmt 5
"INSERT INTO t3 VALUES (fanta)" |
|3 | jump 2|
+-----+----------------------------------------+
4 rows in set (0.00 sec)
SHOW PROCEDURE STATUS
[LIKE 'pattern' | WHEREexpr]
这个也是mysql的一个扩展功能，它展示的是一个存储过程的特有属性，如名字、类型、创建者、修改日期等等
mysql> SHOW PROCEDURE STATUS LIKE 'sp1'\G
*************************** 1. row
***************************
Db: test
Name:
sp1
Type: PROCEDURE
Definer: testuser@localhost
Modified: 2004-08-03 15:29:37
Created: 2004-08-03 15:29:37
Security_type: DEFINER
Comment:
character_set_client: latin1
collation_connection: latin1_swedish_ci
Database
Collation: latin1_swedish_ci
SHOW [FULL] PROCESSLIST
展示sever上正在跑着的线程
mysql> show processlist\G;
*************************** 1. row
***************************
Id: 3
User: root
Host: localhost
db: rec_bak
Command: Query
Time: 0
State: NULL
Info: show
processlist
1 row in set (0.00 sec)
SHOW PROFILES
SHOW PROFILE [type[,type] ... ]
[FOR QUERYn]
[LIMITrow_count[OFFSEToffset]]
type:
ALL
| BLOCK IO
| CONTEXT SWITCHES
| CPU
| IPC
| MEMORY
| PAGE FAULTS
| SOURCE
| SWAPS
显示会话中语句执行时的资源分配概要
mysql> SELECT @@profiling;
+-------------+
| @@profiling |
+-------------+
|0 |
+-------------+
1 row in set (0.00 sec)
mysql> SET profiling = 1;
Query OK, 0 rows affected (0.00 sec)
mysql> DROP TABLE IF EXISTS t1;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> CREATE TABLE T1 (id INT);
Query OK, 0 rows affected (0.01 sec)
mysql> SHOW PROFILES;
+----------+----------+--------------------------+
| Query_ID | Duration | Query|
+----------+----------+--------------------------+
|0 |
0.000088 | SET PROFILING = 1|
|1 |
0.000136 | DROP TABLE IF EXISTS t1|
|2 |
0.011947 | CREATE TABLE t1 (id INT) |
+----------+----------+--------------------------+
3 rows in set (0.00 sec)
mysql> SHOW PROFILE;
+----------------------+----------+
| Status| Duration |
+----------------------+----------+
| checking permissions | 0.000040 |
| creating table| 0.000056 |
| After create| 0.011363 |
| query end| 0.000375 |
| freeing items| 0.000089 |
| logging slow query| 0.000019 |
| cleaning up| 0.000005 |
+----------------------+----------+
7 rows in set (0.00 sec)
mysql> SHOW PROFILE FOR QUERY 1;
+--------------------+----------+
| Status| Duration |
+--------------------+----------+
| query end| 0.000107 |
| freeing items| 0.000008 |
| logging slow query | 0.000015 |
| cleaning up| 0.000006 |
+--------------------+----------+
4 rows in set (0.00 sec)
mysql> SHOW PROFILE CPU FOR QUERY 2;
+----------------------+----------+----------+------------+
| Status| Duration | CPU_user | CPU_system |
+----------------------+----------+----------+------------+
| checking permissions | 0.000040 | 0.000038 |0.000002 |
| creating table| 0.000056 | 0.000028 |0.000028
|
| After create| 0.011363 | 0.000217 |0.001571
|
| query end| 0.000375 | 0.000013 |0.000028 |
| freeing items| 0.000089 | 0.000010 |0.000014
|
| logging slow query| 0.000019 | 0.000009 |0.000010
|
| cleaning up| 0.000005 | 0.000003 |0.000002
|
+----------------------+----------+----------+------------+
7 rows in set (0.00 sec)
SHOW SCHEDULER STATUS
相关事件调度的调试信息。适用于5.1.11调试版，在5.1.12及以后的版本不再支持该语句。其输入可能如下：
+--------------------------------+---------------------+
| Name| Value|
+--------------------------------+---------------------+
| scheduler state| INITIALIZED|
| thread_id| NULL|
| scheduler last locked at| init_scheduler::313 |
| scheduler last unlocked at| init_scheduler::318 |
| scheduler waiting on condition | 0|
| scheduler workers count| 0|
| scheduler executed events| 0|
| scheduler data locked| 0|
| queue element count| 1|
| queue data locked| 0|
| queue data attempting lock| 0|
| queue last locked at| create_event::218|
| queue last unlocked at| create_event::222|
| queue last attempted lock at| ::0|
| queue waiting on condition| 0|
| next activation at|0-00-00 00:00:00 |
+--------------------------------+---------------------+
SHOW SLAVE HOSTS
展示在master上登记过的slave机器的相关信息
mysql> SHOW SLAVE HOSTS;
+------------+-----------+------+-----------+
| Server_id|
Host| Port | Master_id |
+------------+-----------+------+-----------+
|192168010 |
iconnect2 | 3306 | 192168011 |
| 1921680101 | athena| 3306 | 192168011 |
+------------+-----------+------+-----------+
SHOW SLAVE STATUS
显示slave线程基本参数的状态信息
mysql> SHOW SLAVE STATUS\G
*************************** 1. row
***************************
Slave_IO_State: Waiting for master to send event
Master_Host: localhost
Master_User: root
Master_Port: 3306
Connect_Retry: 3
Master_Log_File: gbichot-bin.005
Read_Master_Log_Pos: 79
Relay_Log_File: gbichot-relay-bin.005
Relay_Log_Pos: 548
Relay_Master_Log_File:
gbichot-bin.005
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 79
Relay_Log_Space: 552
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master:
8
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
SHOW [GLOBAL | SESSION] STATUS
[LIKE 'pattern' | WHEREexpr]
显示server的相关状态信息
mysql> show status like 'Up%';
+---------------------------+-------+
| Variable_name| Value |
+---------------------------+-------+
| Uptime| 13301 |
| Uptime_since_flush_status | 13301 |
+---------------------------+-------+
2 rows in set (0.00 sec)
SHOW TABLE STATUS [{FROM | IN}db_name]
[LIKE 'pattern' | WHEREexpr]
有点类似于show tables，但该语提供了更多的非临时表的相关信息。
e.g.q
mysql> show table status from rec_bak like
'admin_user'\G;
*************************** 1. row
***************************
Name:
admin_user
Engine:
InnoDB
Version: 10
Row_format:
Compact
Rows: 44
Avg_row_length:
372
Data_length:
16384
Max_data_length: 0
Index_length: 0
Data_free:
9437184
Auto_increment: 48
Create_time:
2011-08-15 16:11:41
Update_time:
NULL
Check_time:
NULL
Collation:
utf8_general_ci
Checksum:
NULL
Create_options:
avg_row_length=1170
Comment:
1 row in set (0.00 sec)
e.g.2
mysql> show tables from rec_bak like 'admin_user'\G;
*************************** 1. row
***************************
Tables_in_rec_bak (admin_user): admin_user
1 row in set (0.00 sec)
SHOW TRIGGERS [{FROM | IN}db_name]
[LIKE 'pattern' | WHEREexpr]
列出某数据库内定义的triggers.
mysql> SHOW TRIGGERS LIKE 'acc%'\G
*************************** 1. row ***************************
Trigger: ins_sum
Event: INSERT
Table: account
Statement: SET @sum = @sum + NEW.amount
Timing: BEFORE
Created: NULL
sql_mode:
Definer:
myname@localhost
character_set_client: latin1
collation_connection: latin1_swedish_ci
Database
Collation: latin1_swedish_ci
SHOW [GLOBAL | SESSION] VARIABLES
[LIKE 'pattern' | WHEREexpr]
列出mysql的系统变量
mysql> show variables like 'log_bin%';
+---------------------------------+-------+
| Variable_name| Value |
+---------------------------------+-------+
| log_bin| ON|
| log_bin_trust_function_creators | OFF|
| log_bin_trust_routine_creators| OFF|
+---------------------------------+-------+
3 rows in set (0.00 sec)
SHOW WARNINGS [LIMIT [offset,]row_count]
SHOW COUNT(*) WARNINGS
类似show errors；不过该语句显示的是当前会话中最后一个语句执行所产的的错误、警告等相关信息。
e.g.1
mysql> show war;
ERROR 1064 (42000): You have an error in your SQL syntax;
check the manual that corresponds to your MySQL server version for the right
syntax to use near 'war' at line 1
mysql> show warnings\G;
*************************** 1. row
***************************
Level: Error
Code: 1064
Message: You have an error in your SQL syntax; check the
manual that corresponds to your MySQL server version for the right syntax to
use near 'war' at line 1
1 row in set (0.00 sec)
e.g.2
mysql> show databases;
+--------------------+
| Database|
+--------------------+
| information_schema |
| mysql|
| rec_bak|
| test|
+--------------------+
4 rows in set (0.03 sec)
mysql> show warnings\G;
Empty set (0.00 sec)
