~drizzle-trunk/drizzle/development

drop table if exists t1,t2;

set @my_key_buffer_size           =@@global.key_buffer_size;

set @my_max_connect_errors        =@@global.max_connect_errors;

set @my_max_heap_table_size       =@@global.max_heap_table_size;

set @my_max_join_size             =@@global.max_join_size;

set @my_drizzle_protocol_buffer_length =@@global.drizzle_protocol_buffer_length;

set @my_server_id                 =@@global.server_id;

set @my_storage_engine            =@@global.storage_engine;

set @my_myisam_sort_buffer_size	  =@@global.myisam_sort_buffer_size;

set @`test`=1;

select @test, @`test`, @TEST, @`TEST`, @"teSt";

@test	@`test`	@TEST	@`TEST`	@"teSt"

1	1	1	1	1

set @TEST=2;

select @test, @`test`, @TEST, @`TEST`, @"teSt";

@test	@`test`	@TEST	@`TEST`	@"teSt"

2	2	2	2	2

set @"tEST"=3;

select @test, @`test`, @TEST, @`TEST`, @"teSt";

@test	@`test`	@TEST	@`TEST`	@"teSt"

3	3	3	3	3

set @`TeST`=4;

select @test, @`test`, @TEST, @`TEST`, @"teSt";

@test	@`test`	@TEST	@`TEST`	@"teSt"

4	4	4	4	4

select @`teST`:=5;

@`teST`:=5

5

select @test, @`test`, @TEST, @`TEST`, @"teSt";

@test	@`test`	@TEST	@`TEST`	@"teSt"

5	5	5	5	5

set @select=2,@t5=1.23456;

select @`select`,@not_used;

@`select`	@not_used

2	NULL

set @test_int=10,@test_double=1e-10,@test_string="abcdeghi",@test_string2="abcdefghij",@select=NULL;

select @test_int,@test_double,@test_string,@test_string2,@select;

@test_int	@test_double	@test_string	@test_string2	@select

10	0.0000000001	abcdeghi	abcdefghij	NULL

set @test_int="hello",@test_double="hello",@test_string="hello",@test_string2="hello";

select @test_int,@test_double,@test_string,@test_string2;

@test_int	@test_double	@test_string	@test_string2

hello	hello	hello	hello

set @test_int="hellohello",@test_double="hellohello",@test_string="hellohello",@test_string2="hellohello";

select @test_int,@test_double,@test_string,@test_string2;

@test_int	@test_double	@test_string	@test_string2

hellohello	hellohello	hellohello	hellohello

set @test_int=null,@test_double=null,@test_string=null,@test_string2=null;

select @test_int,@test_double,@test_string,@test_string2;

@test_int	@test_double	@test_string	@test_string2

NULL	NULL	NULL	NULL

select @t1:=(@t2:=1)+@t3:=4,@t1,@t2,@t3;

@t1:=(@t2:=1)+@t3:=4	@t1	@t2	@t3

5	5	1	4

explain extended select @t1:=(@t2:=1)+@t3:=4,@t1,@t2,@t3;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

Warnings:

Note	1003	select (@t1:=((@t2:=1) + (@t3:=4))) AS `@t1:=(@t2:=1)+@t3:=4`,(@t1) AS `@t1`,(@t2) AS `@t2`,(@t3) AS `@t3`

select @t5;

@t5

1.23456

CREATE TABLE t1 (c_id INT NOT NULL, c_name VARCHAR(250), c_country VARCHAR(250), PRIMARY KEY(c_id));

INSERT INTO t1 VALUES (1,'Bozo','USA'),(2,'Ronald','USA'),(3,'Kinko','IRE'),(4,'Mr. Floppy','GB');

SELECT @min_cid:=min(c_id), @max_cid:=max(c_id) from t1;

@min_cid:=min(c_id)	@max_cid:=max(c_id)

1	4

SELECT * FROM t1 WHERE c_id=@min_cid OR c_id=@max_cid;

c_id	c_name	c_country

1	Bozo	USA

4	Mr. Floppy	GB

SELECT * FROM t1 WHERE c_id=@min_cid OR c_id=@max_cid OR c_id=666;

c_id	c_name	c_country

1	Bozo	USA

4	Mr. Floppy	GB

ALTER TABLE t1 DROP PRIMARY KEY;

select * from t1 where c_id=@min_cid OR c_id=@max_cid;

c_id	c_name	c_country

1	Bozo	USA

4	Mr. Floppy	GB

drop table t1;

set GLOBAL max_join_size=10;

set max_join_size=100;

show variables like 'max_join_size';

Variable_name	Value

max_join_size	100

select * from information_schema.session_variables where variable_name like 'max_join_size';

VARIABLE_NAME	VARIABLE_VALUE

MAX_JOIN_SIZE	100

show global variables like 'max_join_size';

Variable_name	Value

max_join_size	10

select * from information_schema.global_variables where variable_name like 'max_join_size';

VARIABLE_NAME	VARIABLE_VALUE

MAX_JOIN_SIZE	10

set GLOBAL max_join_size=2000;

show global variables like 'max_join_size';

Variable_name	Value

max_join_size	2000

select * from information_schema.global_variables where variable_name like 'max_join_size';

VARIABLE_NAME	VARIABLE_VALUE

MAX_JOIN_SIZE	2000

set max_join_size=DEFAULT;

show variables like 'max_join_size';

Variable_name	Value

max_join_size	2000

select * from information_schema.session_variables where variable_name like 'max_join_size';

VARIABLE_NAME	VARIABLE_VALUE

MAX_JOIN_SIZE	2000

set GLOBAL max_join_size=DEFAULT;

show global variables like 'max_join_size';

Variable_name	Value

max_join_size	2147483647

select * from information_schema.global_variables where variable_name like 'max_join_size';

VARIABLE_NAME	VARIABLE_VALUE

MAX_JOIN_SIZE	2147483647

set @@max_join_size=1000, @@global.max_join_size=2000;

select @@local.max_join_size, @@global.max_join_size;

@@local.max_join_size	@@global.max_join_size

1000	2000

select @@identity,  length(@@version)>0;

@@identity	length(@@version)>0

0	1

select @@VERSION=version();

@@VERSION=version()

1

select last_insert_id(345);

last_insert_id(345)

345

explain extended select last_insert_id(345);

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

Warnings:

Note	1003	select last_insert_id(345) AS `last_insert_id(345)`

select @@IDENTITY,last_insert_id(), @@identity;

@@IDENTITY	last_insert_id()	@@identity

345	345	345

explain extended select @@IDENTITY,last_insert_id(), @@identity;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

Warnings:

Note	1003	select 345 AS `@@IDENTITY`,last_insert_id() AS `last_insert_id()`,345 AS `@@identity`

set global timed_mutexes=ON;

show variables like 'timed_mutexes';

Variable_name	Value

timed_mutexes	ON

select * from information_schema.session_variables where variable_name like 'timed_mutexes';

VARIABLE_NAME	VARIABLE_VALUE

TIMED_MUTEXES	ON

set global timed_mutexes=0;

show variables like 'timed_mutexes';

Variable_name	Value

timed_mutexes	OFF

select * from information_schema.session_variables where variable_name like 'timed_mutexes';

VARIABLE_NAME	VARIABLE_VALUE

TIMED_MUTEXES	OFF

set storage_engine=MYISAM, storage_engine="MEMORY";

show local variables like 'storage_engine';

Variable_name	Value

storage_engine	MEMORY

select * from information_schema.session_variables where variable_name like 'storage_engine';

VARIABLE_NAME	VARIABLE_VALUE

STORAGE_ENGINE	MEMORY

show global variables like 'storage_engine';

Variable_name	Value

storage_engine	InnoDB

select * from information_schema.global_variables where variable_name like 'storage_engine';

VARIABLE_NAME	VARIABLE_VALUE

STORAGE_ENGINE	InnoDB

set GLOBAL myisam_max_sort_file_size=2000000;

show global variables like 'myisam_max_sort_file_size';

Variable_name	Value

myisam_max_sort_file_size	2000000

select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';

VARIABLE_NAME	VARIABLE_VALUE

MYISAM_MAX_SORT_FILE_SIZE	2000000

set GLOBAL myisam_max_sort_file_size=default;

show global variables like 'myisam_max_sort_file_size';

Variable_name	Value

myisam_max_sort_file_size	2147483647

select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';

VARIABLE_NAME	VARIABLE_VALUE

MYISAM_MAX_SORT_FILE_SIZE	2147483647

set global drizzle_protocol_buffer_length=1024;

show global variables like 'drizzle_protocol_buffer_%';

Variable_name	Value

drizzle_protocol_buffer_length	1024

select * from information_schema.global_variables where variable_name like 'drizzle_protocol_buffer_%';

VARIABLE_NAME	VARIABLE_VALUE

DRIZZLE_PROTOCOL_BUFFER_LENGTH	1024

show global variables like 'drizzle_protocol_buffer_%';

Variable_name	Value

drizzle_protocol_buffer_length	1024

select * from information_schema.global_variables where variable_name like 'drizzle_protocol_buffer_%';

VARIABLE_NAME	VARIABLE_VALUE

DRIZZLE_PROTOCOL_BUFFER_LENGTH	1024

set global drizzle_protocol_buffer_length=1;

Warnings:

Error	1292	Truncated incorrect buffer_length value: '1'

show variables like 'drizzle_protocol_buffer_length';

Variable_name	Value

drizzle_protocol_buffer_length	1024

set global drizzle_protocol_buffer_length=2000000000;

Warnings:

Error	1292	Truncated incorrect buffer_length value: '2000000000'

show variables like 'drizzle_protocol_buffer_length';

Variable_name	Value

drizzle_protocol_buffer_length	1048576

show variables like '%alloc%';

Variable_name	Value

innodb_use_sys_malloc	ON

query_alloc_block_size	8192

query_prealloc_size	8192

range_alloc_block_size	

transaction_alloc_block_size	8192

transaction_prealloc_size	4096

select * from information_schema.session_variables where variable_name like '%alloc%';

VARIABLE_NAME	VARIABLE_VALUE

INNODB_USE_SYS_MALLOC	ON

QUERY_ALLOC_BLOCK_SIZE	8192

QUERY_PREALLOC_SIZE	8192

RANGE_ALLOC_BLOCK_SIZE	

TRANSACTION_ALLOC_BLOCK_SIZE	8192

TRANSACTION_PREALLOC_SIZE	4096

set @@range_alloc_block_size=1024*16;

set @@query_alloc_block_size=1024*17+2;

set @@query_prealloc_size=1024*18;

set @@transaction_alloc_block_size=1024*20-1;

set @@transaction_prealloc_size=1024*21-1;

select @@query_alloc_block_size;

@@query_alloc_block_size

17408

show variables like '%alloc%';

Variable_name	Value

innodb_use_sys_malloc	ON

query_alloc_block_size	17408

query_prealloc_size	18432

range_alloc_block_size	

transaction_alloc_block_size	19456

transaction_prealloc_size	20480

select * from information_schema.session_variables where variable_name like '%alloc%';

VARIABLE_NAME	VARIABLE_VALUE

INNODB_USE_SYS_MALLOC	ON

QUERY_ALLOC_BLOCK_SIZE	17408

QUERY_PREALLOC_SIZE	18432

RANGE_ALLOC_BLOCK_SIZE	

TRANSACTION_ALLOC_BLOCK_SIZE	19456

TRANSACTION_PREALLOC_SIZE	20480

set @@range_alloc_block_size=default;

set @@query_alloc_block_size=default, @@query_prealloc_size=default;

set transaction_alloc_block_size=default, @@transaction_prealloc_size=default;

show variables like '%alloc%';

Variable_name	Value

innodb_use_sys_malloc	ON

query_alloc_block_size	8192

query_prealloc_size	8192

range_alloc_block_size	

transaction_alloc_block_size	8192

transaction_prealloc_size	4096

select * from information_schema.session_variables where variable_name like '%alloc%';

VARIABLE_NAME	VARIABLE_VALUE

INNODB_USE_SYS_MALLOC	ON

QUERY_ALLOC_BLOCK_SIZE	8192

QUERY_PREALLOC_SIZE	8192

RANGE_ALLOC_BLOCK_SIZE	

TRANSACTION_ALLOC_BLOCK_SIZE	8192

TRANSACTION_PREALLOC_SIZE	4096

SELECT @@version LIKE 'non-existent';

@@version LIKE 'non-existent'

0

SELECT @@version_compile_os LIKE 'non-existent';

@@version_compile_os LIKE 'non-existent'

0

set unknown_variable=1;

ERROR HY000: Unknown system variable 'unknown_variable'

set max_join_size="hello";

ERROR 42000: Incorrect argument type to variable 'max_join_size'

set storage_engine=UNKNOWN_TABLE_TYPE;

ERROR 42000: Unknown table engine 'UNKNOWN_TABLE_TYPE'

set GLOBAL storage_engine=DEFAULT;

ERROR 42000: Variable 'storage_engine' doesn't have a default value

set global autocommit=1;

ERROR HY000: Variable 'autocommit' is a SESSION variable and can't be used with SET GLOBAL

select @@global.timestamp;

ERROR HY000: Variable 'timestamp' is a SESSION variable

set @@version='';

ERROR HY000: Variable 'version' is a read only variable

set myisam_max_sort_file_size=100;

ERROR HY000: Variable 'myisam_max_sort_file_size' is a GLOBAL variable and should be set with SET GLOBAL

set @@SQL_WARNINGS=NULL;

ERROR 42000: Variable 'sql_warnings' can't be set to the value of 'NULL'

set autocommit=1;

select @@autocommit;

@@autocommit

1

set bulk_insert_buffer_size=100;

set join_buffer_size=100;

Warnings:

Error	1292	Truncated incorrect join_buffer_size value: '100'

set last_insert_id=1;

set max_allowed_packet=100;

Warnings:

Error	1292	Truncated incorrect max_allowed_packet value: '100'

set global max_connect_errors=100;

set max_heap_table_size=100;

Warnings:

Error	1292	Truncated incorrect max_heap_table_size value: '100'

set max_join_size=100;

set max_sort_length=100;

set global max_write_lock_count=100;

set global myisam_sort_buffer_size=100;

Warnings:

Error	1292	Truncated incorrect sort_buffer_size value: '100'

set global drizzle_protocol_buffer_length=100;

Warnings:

Error	1292	Truncated incorrect buffer_length value: '100'

set read_buffer_size=100;

Warnings:

Error	1292	Truncated incorrect read_buffer_size value: '100'

set read_rnd_buffer_size=100;

set global server_id=100;

set sort_buffer_size=100;

Warnings:

Error	1292	Truncated incorrect sort_buffer_size value: '100'

set sql_big_selects=1;

set sql_buffer_result=1;

set sql_select_limit=1;

set sql_select_limit=default;

set sql_warnings=1;

set global table_open_cache=100;

set storage_engine=myisam;

set timestamp=1, timestamp=default;

set tmp_table_size=100;

Warnings:

Error	1292	Truncated incorrect tmp_table_size value: '100'

set tx_isolation="READ-COMMITTED";

create temporary table t1 (a int not null auto_increment, primary key(a));

create temporary table t2 (a int not null auto_increment, primary key(a));

insert into t1 values(null),(null),(null);

insert into t2 values(null),(null),(null);

set global key_buffer_size=100000;

select @@key_buffer_size;

@@key_buffer_size

98304

select * from t1 where a=2;

a

2

select * from t2 where a=3;

a

3

check table t1,t2;

Table	Op	Msg_type	Msg_text

test.t1	check	status	OK

test.t2	check	status	OK

select max(a) +1, max(a) +2 into @xx,@yy from t1;

drop table t1,t2;

select @@xxxxxxxxxx;

ERROR HY000: Unknown system variable 'xxxxxxxxxx'

select 1;

1

1

select @@session.key_buffer_size;

ERROR HY000: Variable 'key_buffer_size' is a GLOBAL variable

set global myisam_max_sort_file_size=4294967296;

show global variables like 'myisam_max_sort_file_size';

Variable_name	Value

myisam_max_sort_file_size	MAX_FILE_SIZE

select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';

VARIABLE_NAME	VARIABLE_VALUE

MYISAM_MAX_SORT_FILE_SIZE	MAX_FILE_SIZE

set global myisam_max_sort_file_size=default;

set @@global.global.key_buffer_size= 1;

ERROR HY000: Unknown system variable 'global'

set GLOBAL global.key_buffer_size= 1;

ERROR HY000: Unknown system variable 'global'

SELECT @@global.global.key_buffer_size;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your Drizzle server version for the right syntax to use near 'key_buffer_size' at line 1

SELECT @@global.session.key_buffer_size;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your Drizzle server version for the right syntax to use near 'key_buffer_size' at line 1

SELECT @@global.local.key_buffer_size;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your Drizzle server version for the right syntax to use near 'key_buffer_size' at line 1

create temporary table t1 (

c1 int,

c2 int,

c3 int,

c4 int,

c5 bigint);

show create table t1;

Table	Create Table

t1	CREATE TEMPORARY TABLE `t1` (

  `c1` int DEFAULT NULL,

  `c2` int DEFAULT NULL,

  `c3` int DEFAULT NULL,

  `c4` int DEFAULT NULL,

  `c5` bigint DEFAULT NULL

) ENGINE=MyISAM

drop table t1;

set @arg00= 8, @arg01= 8.8, @arg02= 'a string', @arg03= 0.2e0;

create temporary table t1 as select @arg00 as c1, @arg01 as c2, @arg02 as c3, @arg03 as c4;

show create table t1;

Table	Create Table

t1	CREATE TEMPORARY TABLE `t1` (

  `c1` bigint DEFAULT NULL,

  `c2` decimal(65,30) DEFAULT NULL,

  `c3` text,

  `c4` double DEFAULT NULL

) ENGINE=MyISAM

drop table t1;

SET GLOBAL table_open_cache=-1;

Warnings:

Error	1292	Truncated incorrect table_open_cache value: '18446744073709551615'

SHOW VARIABLES LIKE 'table_open_cache';

Variable_name	Value

table_open_cache	100

SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME LIKE 'table_open_cache';

VARIABLE_NAME	VARIABLE_VALUE

TABLE_OPEN_CACHE	100

SET GLOBAL table_open_cache=DEFAULT;

*** Various tests with LC_TIME_NAMES

*** LC_TIME_NAMES: testing case insensitivity

set @@lc_time_names='ru_ru';

select @@lc_time_names;

@@lc_time_names

ru_RU

*** LC_TIME_NAMES: testing with a user variable

set @lc='JA_JP';

set @@lc_time_names=@lc;

select @@lc_time_names;

@@lc_time_names

ja_JP

*** LC_TIME_NAMES: testing with string expressions

set lc_time_names=concat('de','_','DE');

select @@lc_time_names;

@@lc_time_names

de_DE

set lc_time_names=concat('de','+','DE');

ERROR HY000: Unknown locale: 'de+DE'

select @@lc_time_names;

@@lc_time_names

de_DE

LC_TIME_NAMES: testing with numeric expressions

set @@lc_time_names=1+2;

select @@lc_time_names;

@@lc_time_names

sv_SE

set @@lc_time_names=1/0;

ERROR 42000: Incorrect argument type to variable 'lc_time_names'

select @@lc_time_names;

@@lc_time_names

sv_SE

set lc_time_names=en_US;

LC_TIME_NAMES: testing NULL and a negative number:

set lc_time_names=NULL;

ERROR 42000: Variable 'lc_time_names' can't be set to the value of 'NULL'

set lc_time_names=-1;

ERROR HY000: Unknown locale: '-1'

select @@lc_time_names;

@@lc_time_names

en_US

LC_TIME_NAMES: testing locale with the last ID:

set lc_time_names=108;

select @@lc_time_names;

@@lc_time_names

zh_HK

LC_TIME_NAMES: testing a number beyond the valid ID range:

set lc_time_names=109;

ERROR HY000: Unknown locale: '109'

select @@lc_time_names;

@@lc_time_names

zh_HK

LC_TIME_NAMES: testing that 0 is en_US:

set lc_time_names=0;

select @@lc_time_names;

@@lc_time_names

en_US

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

en_US	en_US

set @@global.lc_time_names=fr_FR;

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

fr_FR	en_US

New connection

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

fr_FR	fr_FR

set @@lc_time_names=ru_RU;

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

fr_FR	ru_RU

Returnung to default connection

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

fr_FR	en_US

set lc_time_names=default;

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

fr_FR	fr_FR

set @@global.lc_time_names=default;

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

en_US	fr_FR

set @@lc_time_names=default;

select @@global.lc_time_names, @@lc_time_names;

@@global.lc_time_names	@@lc_time_names

en_US	en_US

set @test = @@query_prealloc_size;

set @@query_prealloc_size = @test;

select @@query_prealloc_size = @test;

@@query_prealloc_size = @test

1

End of 4.1 tests

create temporary table t1 (a int);

select a into @x from t1;

Warnings:

Warning	1329	No data - zero rows fetched, selected, or processed

show warnings;

Level	Code	Message

Warning	1329	No data - zero rows fetched, selected, or processed

drop table t1;

set @@warning_count=1;

ERROR HY000: Variable 'warning_count' is a read only variable

set @@global.error_count=1;

ERROR HY000: Variable 'error_count' is a read only variable

select @@character_set_system;

ERROR HY000: Unknown system variable 'character_set_system'

set global character_set_system = utf8;

ERROR HY000: Unknown system variable 'character_set_system'

set @@global.version_compile_os='234';

ERROR HY000: Variable 'version_compile_os' is a read only variable

set @@global.character_set_filesystem=utf8;

ERROR HY000: Unknown system variable 'character_set_filesystem'

set character_set_filesystem=utf8;

ERROR HY000: Unknown system variable 'character_set_filesystem'

set @old_sql_big_selects = @@sql_big_selects;

set @@sql_big_selects = 1;

show variables like 'sql_big_selects';

Variable_name	Value

sql_big_selects	ON

set @@sql_big_selects = @old_sql_big_selects;

set @@sql_notes = 0, @@sql_warnings = 0;

show variables like 'sql_notes';

Variable_name	Value

sql_notes	OFF

show variables like 'sql_warnings';

Variable_name	Value

sql_warnings	OFF

set @@sql_notes = 1, @@sql_warnings = 1;

show variables like 'sql_notes';

Variable_name	Value

sql_notes	ON

show variables like 'sql_warnings';

Variable_name	Value

sql_warnings	ON

select @@version, @@version_comment, @@version_compile_machine,

@@version_compile_os;

@@version	@@version_comment	@@version_compile_machine	@@version_compile_os

#	#	#	#

select @@basedir, @@datadir, @@tmpdir;

@@basedir	@@datadir	@@tmpdir

#	#	#

show variables like 'basedir';

Variable_name	Value

basedir	#

show variables like 'datadir';

Variable_name	Value

datadir	#

show variables like 'tmpdir';

Variable_name	Value

tmpdir	#

select @@"";

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your Drizzle server version for the right syntax to use near '""' at line 1

select @@&;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your Drizzle server version for the right syntax to use near '&' at line 1

select @@@;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your Drizzle server version for the right syntax to use near '@' at line 1

select @@hostname;

@@hostname

#

set @@hostname= "anothername";

ERROR HY000: Variable 'hostname' is a read only variable