mariadb/mysql-test/r/sql_mode.result
unknown 405f82d390 Patch for the following bugs:
- BUG#11986: Stored routines and triggers can fail if the code
    has a non-ascii symbol
  - BUG#16291: mysqldump corrupts string-constants with non-ascii-chars
  - BUG#19443: INFORMATION_SCHEMA does not support charsets properly
  - BUG#21249: Character set of SP-var can be ignored
  - BUG#25212: Character set of string constant is ignored (stored routines)
  - BUG#25221: Character set of string constant is ignored (triggers)

There were a few general problems that caused these bugs:
1. Character set information of the original (definition) query for views,
   triggers, stored routines and events was lost.
2. mysqldump output query in client character set, which can be
   inappropriate to encode definition-query.
3. INFORMATION_SCHEMA used strings with mixed encodings to display object
   definition;

1. No query-definition-character set.

In order to compile query into execution code, some extra data (such as
environment variables or the database character set) is used. The problem
here was that this context was not preserved. So, on the next load it can
differ from the original one, thus the result will be different.

The context contains the following data:
  - client character set;
  - connection collation (character set and collation);
  - collation of the owner database;

The fix is to store this context and use it each time we parse (compile)
and execute the object (stored routine, trigger, ...).

2. Wrong mysqldump-output.

The original query can contain several encodings (by means of character set
introducers). The problem here was that we tried to convert original query
to the mysqldump-client character set.

Moreover, we stored queries in different character sets for different
objects (views, for one, used UTF8, triggers used original character set).

The solution is
  - to store definition queries in the original character set;
  - to change SHOW CREATE statement to output definition query in the
    binary character set (i.e. without any conversion);
  - introduce SHOW CREATE TRIGGER statement;
  - to dump special statements to switch the context to the original one
    before dumping and restore it afterwards.

Note, in order to preserve the database collation at the creation time,
additional ALTER DATABASE might be used (to temporary switch the database
collation back to the original value). In this case, ALTER DATABASE
privilege will be required. This is a backward-incompatible change.

3. INFORMATION_SCHEMA showed non-UTF8 strings

The fix is to generate UTF8-query during the parsing, store it in the object
and show it in the INFORMATION_SCHEMA.

Basically, the idea is to create a copy of the original query convert it to
UTF8. Character set introducers are removed and all text literals are
converted to UTF8.

This UTF8 query is intended to provide user-readable output. It must not be
used to recreate the object.  Specialized SHOW CREATE statements should be
used for this.

The reason for this limitation is the following: the original query can
contain symbols from several character sets (by means of character set
introducers).

Example:

  - original query:
    CREATE VIEW v1 AS SELECT _cp1251 'Hello' AS c1;

  - UTF8 query (for INFORMATION_SCHEMA):
    CREATE VIEW v1 AS SELECT 'Hello' AS c1;


client/mysqldump.c:
  Set original character set and collation before dumping definition query.
include/my_sys.h:
  Move out-parameter to the end of list.
mysql-test/lib/mtr_report.pl:
  Ignore server-warnings during the test case.
mysql-test/r/create.result:
  Update result file.
mysql-test/r/ctype_cp932_binlog_stm.result:
  Update result file.
mysql-test/r/events.result:
  Update result file.
mysql-test/r/events_bugs.result:
  Update result file.
mysql-test/r/events_grant.result:
  Update result file.
mysql-test/r/func_in.result:
  Update result file.
mysql-test/r/gis.result:
  Update result file.
mysql-test/r/grant.result:
  Update result file.
mysql-test/r/information_schema.result:
  Update result file.
mysql-test/r/information_schema_db.result:
  Update result file.
mysql-test/r/lowercase_view.result:
  Update result file.
mysql-test/r/mysqldump.result:
  Update result file.
mysql-test/r/ndb_sp.result:
  Update result file.
mysql-test/r/ps.result:
  Update result file.
mysql-test/r/rpl_replicate_do.result:
  Update result file.
mysql-test/r/rpl_sp.result:
  Update result file.
mysql-test/r/rpl_trigger.result:
  Update result file.
mysql-test/r/rpl_view.result:
  Update result file.
mysql-test/r/show_check.result:
  Update result file.
mysql-test/r/skip_grants.result:
  Update result file.
mysql-test/r/sp-destruct.result:
  Update result file.
mysql-test/r/sp-error.result:
  Update result file.
mysql-test/r/sp-security.result:
  Update result file.
mysql-test/r/sp.result:
  Update result file.
mysql-test/r/sql_mode.result:
  Update result file.
mysql-test/r/system_mysql_db.result:
  Update result file.
mysql-test/r/temp_table.result:
  Update result file.
mysql-test/r/trigger-compat.result:
  Update result file.
mysql-test/r/trigger-grant.result:
  Update result file.
mysql-test/r/trigger.result:
  Update result file.
mysql-test/r/view.result:
  Update result file.
mysql-test/r/view_grant.result:
  Update result file.
mysql-test/t/events.test:
  Update test case (new columns added).
mysql-test/t/information_schema.test:
  Update test case (new columns added).
mysql-test/t/show_check.test:
  Test case for SHOW CREATE TRIGGER in prepared statements and
  stored routines.
mysql-test/t/sp-destruct.test:
  Update test case (new columns added).
mysql-test/t/sp.test:
  Update test case (new columns added).
mysql-test/t/view.test:
  Update test.
mysys/charset.c:
  Move out-parameter to the end of list.
scripts/mysql_system_tables.sql:
  Add new columns to mysql.proc and mysql.event.
scripts/mysql_system_tables_fix.sql:
  Add new columns to mysql.proc and mysql.event.
sql/event_data_objects.cc:
  Support new attributes for events.
sql/event_data_objects.h:
  Support new attributes for events.
sql/event_db_repository.cc:
  Support new attributes for events.
sql/event_db_repository.h:
  Support new attributes for events.
sql/events.cc:
  Add new columns to SHOW CREATE event resultset.
sql/mysql_priv.h:
  1. Introduce Object_creation_ctx;
  2. Introduce SHOW CREATE TRIGGER;
  3. Introduce auxilary functions.
sql/sp.cc:
  Add support for new store routines attributes.
sql/sp_head.cc:
  Add support for new store routines attributes.
sql/sp_head.h:
  Add support for new store routines attributes.
sql/sql_lex.cc:
  Generate UTF8-body on parsing/lexing.
sql/sql_lex.h:
  1. Generate UTF8-body on parsing/lexing.
  2. Introduce SHOW CREATE TRIGGER.
sql/sql_parse.cc:
  Introduce SHOW CREATE TRIGGER.
sql/sql_partition.cc:
  Update parse_sql().
sql/sql_prepare.cc:
  Update parse_sql().
sql/sql_show.cc:
  Support new attributes for views
sql/sql_trigger.cc:
  Support new attributes for views
sql/sql_trigger.h:
  Support new attributes for views
sql/sql_view.cc:
  Support new attributes for views
sql/sql_yacc.yy:
  1. Add SHOW CREATE TRIGGER statement.
  2. Generate UTF8-body for views, stored routines, triggers and events.
sql/table.cc:
  Introduce Object_creation_ctx.
sql/table.h:
  Introduce Object_creation_ctx.
sql/share/errmsg.txt:
  Add new errors.
mysql-test/include/ddl_i18n.check_events.inc:
  Aux file for test suite.
mysql-test/include/ddl_i18n.check_sp.inc:
  Aux file for test suite.
mysql-test/include/ddl_i18n.check_triggers.inc:
  Aux file for test suite.
mysql-test/include/ddl_i18n.check_views.inc:
  Aux file for test suite.
mysql-test/include/have_cp1251.inc:
  Aux file for test suite.
mysql-test/include/have_cp866.inc:
  Aux file for test suite.
mysql-test/include/have_koi8r.inc:
  Aux file for test suite.
mysql-test/include/have_utf8.inc:
  Aux file for test suite.
mysql-test/r/ddl_i18n_koi8r.result:
  Result file.
mysql-test/r/ddl_i18n_utf8.result:
  Result file.
mysql-test/r/have_cp1251.require:
  Aux file for test suite.
mysql-test/r/have_cp866.require:
  Aux file for test suite.
mysql-test/r/have_koi8r.require:
  Aux file for test suite.
mysql-test/r/have_utf8.require:
  Aux file for test suite.
mysql-test/t/ddl_i18n_koi8r.test:
  Complete koi8r test case for the CS patch.
mysql-test/t/ddl_i18n_utf8.test:
  Complete utf8 test case for the CS patch.
2007-06-28 21:34:54 +04:00

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Text

drop table if exists t1,t2,v1,v2;
drop view if exists t1,t2,v1,v2;
CREATE TABLE `t1` (
a int not null auto_increment,
`pseudo` varchar(35) character set latin2 NOT NULL default '',
`email` varchar(60) character set latin2 NOT NULL default '',
PRIMARY KEY (a),
UNIQUE KEY `email` USING BTREE (`email`)
) ENGINE=HEAP CHARSET=latin1 ROW_FORMAT DYNAMIC;
set @@sql_mode="";
show variables like 'sql_mode';
Variable_name Value
sql_mode
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL AUTO_INCREMENT,
`pseudo` varchar(35) CHARACTER SET latin2 NOT NULL DEFAULT '',
`email` varchar(60) CHARACTER SET latin2 NOT NULL DEFAULT '',
PRIMARY KEY (`a`),
UNIQUE KEY `email` (`email`) USING BTREE
) ENGINE=MEMORY DEFAULT CHARSET=latin1 ROW_FORMAT=DYNAMIC
set @@sql_mode="ansi_quotes";
show variables like 'sql_mode';
Variable_name Value
sql_mode ANSI_QUOTES
show create table t1;
Table Create Table
t1 CREATE TABLE "t1" (
"a" int(11) NOT NULL AUTO_INCREMENT,
"pseudo" varchar(35) CHARACTER SET latin2 NOT NULL DEFAULT '',
"email" varchar(60) CHARACTER SET latin2 NOT NULL DEFAULT '',
PRIMARY KEY ("a"),
UNIQUE KEY "email" ("email") USING BTREE
) ENGINE=MEMORY DEFAULT CHARSET=latin1 ROW_FORMAT=DYNAMIC
set @@sql_mode="no_table_options";
show variables like 'sql_mode';
Variable_name Value
sql_mode NO_TABLE_OPTIONS
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL AUTO_INCREMENT,
`pseudo` varchar(35) CHARACTER SET latin2 NOT NULL DEFAULT '',
`email` varchar(60) CHARACTER SET latin2 NOT NULL DEFAULT '',
PRIMARY KEY (`a`),
UNIQUE KEY `email` (`email`) USING BTREE
)
set @@sql_mode="no_key_options";
show variables like 'sql_mode';
Variable_name Value
sql_mode NO_KEY_OPTIONS
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL AUTO_INCREMENT,
`pseudo` varchar(35) CHARACTER SET latin2 NOT NULL DEFAULT '',
`email` varchar(60) CHARACTER SET latin2 NOT NULL DEFAULT '',
PRIMARY KEY (`a`),
UNIQUE KEY `email` (`email`)
) ENGINE=MEMORY DEFAULT CHARSET=latin1 ROW_FORMAT=DYNAMIC
set @@sql_mode="no_field_options,mysql323,mysql40";
show variables like 'sql_mode';
Variable_name Value
sql_mode NO_FIELD_OPTIONS,MYSQL323,MYSQL40,HIGH_NOT_PRECEDENCE
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL,
`pseudo` varchar(35) NOT NULL DEFAULT '',
`email` varchar(60) NOT NULL DEFAULT '',
PRIMARY KEY (`a`),
UNIQUE KEY `email` (`email`)
) TYPE=HEAP ROW_FORMAT=DYNAMIC
set sql_mode="postgresql,oracle,mssql,db2,maxdb";
select @@sql_mode;
@@sql_mode
PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,POSTGRESQL,ORACLE,MSSQL,DB2,MAXDB,NO_KEY_OPTIONS,NO_TABLE_OPTIONS,NO_FIELD_OPTIONS,NO_AUTO_CREATE_USER
show create table t1;
Table Create Table
t1 CREATE TABLE "t1" (
"a" int(11) NOT NULL,
"pseudo" varchar(35) CHARACTER SET latin2 NOT NULL DEFAULT '',
"email" varchar(60) CHARACTER SET latin2 NOT NULL DEFAULT '',
PRIMARY KEY ("a"),
UNIQUE KEY "email" ("email")
)
drop table t1;
CREATE TABLE t1 (
a char(10),
b char(10) collate latin1_bin,
c binary(10)
) character set latin1;
set @@sql_mode="";
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` char(10) DEFAULT NULL,
`b` char(10) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
`c` binary(10) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
set @@sql_mode="mysql323";
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` char(10) DEFAULT NULL,
`b` char(10) binary DEFAULT NULL,
`c` binary(10) DEFAULT NULL
) TYPE=MyISAM
set @@sql_mode="mysql40";
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` char(10) DEFAULT NULL,
`b` char(10) binary DEFAULT NULL,
`c` binary(10) DEFAULT NULL
) TYPE=MyISAM
drop table t1;
set session sql_mode = '';
create table t1 ( min_num dec(6,6) default .000001);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`min_num` decimal(6,6) DEFAULT '0.000001'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1 ;
set session sql_mode = 'IGNORE_SPACE';
create table t1 ( min_num dec(6,6) default 0.000001);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`min_num` decimal(6,6) DEFAULT '0.000001'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1 ;
create table t1 ( min_num dec(6,6) default .000001);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`min_num` decimal(6,6) DEFAULT '0.000001'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1 ;
set @@SQL_MODE=NULL;
ERROR 42000: Variable 'sql_mode' can't be set to the value of 'NULL'
set session sql_mode=ansi;
create table t1
(f1 integer auto_increment primary key,
f2 timestamp default current_timestamp on update current_timestamp);
show create table t1;
Table Create Table
t1 CREATE TABLE "t1" (
"f1" int(11) NOT NULL AUTO_INCREMENT,
"f2" timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY ("f1")
)
set session sql_mode=no_field_options;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) NOT NULL,
`f2` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`f1`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
SET @OLD_SQL_MODE=@@SQL_MODE, @@SQL_MODE='';
show local variables like 'SQL_MODE';
Variable_name Value
sql_mode
CREATE TABLE t1 (p int not null auto_increment, a varchar(20), primary key(p));
INSERT t1 (a) VALUES
('\\'),
('\n'),
('\b'),
('\r'),
('\t'),
('\x'),
('\a'),
('\aa'),
('\\a'),
('\\aa'),
('_'),
('\_'),
('\\_'),
('\\\_'),
('\\\\_'),
('%'),
('\%'),
('\\%'),
('\\\%'),
('\\\\%')
;
SELECT p, hex(a) FROM t1;
p hex(a)
1 5C
2 0A
3 08
4 0D
5 09
6 78
7 61
8 6161
9 5C61
10 5C6161
11 5F
12 5C5F
13 5C5F
14 5C5C5F
15 5C5C5F
16 25
17 5C25
18 5C25
19 5C5C25
20 5C5C25
delete from t1 where a in ('\n','\r','\t', '\b');
select
masks.p,
masks.a as mask,
examples.a as example
from
t1 as masks
left join t1 as examples on examples.a LIKE masks.a
order by masks.p, example;
p mask example
1 \ \
6 x x
7 a a
8 aa aa
9 \a a
10 \aa aa
11 _ %
11 _ a
11 _ x
11 _ \
11 _ _
12 \_ _
13 \_ _
14 \\_ \%
14 \\_ \%
14 \\_ \a
14 \\_ \_
14 \\_ \_
15 \\_ \%
15 \\_ \%
15 \\_ \a
15 \\_ \_
15 \\_ \_
16 % %
16 % a
16 % aa
16 % x
16 % \
16 % \%
16 % \%
16 % \a
16 % \aa
16 % \\%
16 % \\%
16 % \\_
16 % \\_
16 % \_
16 % \_
16 % _
17 \% %
18 \% %
19 \\% \
19 \\% \%
19 \\% \%
19 \\% \a
19 \\% \aa
19 \\% \\%
19 \\% \\%
19 \\% \\_
19 \\% \\_
19 \\% \_
19 \\% \_
20 \\% \
20 \\% \%
20 \\% \%
20 \\% \a
20 \\% \aa
20 \\% \\%
20 \\% \\%
20 \\% \\_
20 \\% \\_
20 \\% \_
20 \\% \_
DROP TABLE t1;
SET @@SQL_MODE='NO_BACKSLASH_ESCAPES';
show local variables like 'SQL_MODE';
Variable_name Value
sql_mode NO_BACKSLASH_ESCAPES
CREATE TABLE t1 (p int not null auto_increment, a varchar(20), primary key(p));
INSERT t1 (a) VALUES
('\\'),
('\n'),
('\b'),
('\r'),
('\t'),
('\x'),
('\a'),
('\aa'),
('\\a'),
('\\aa'),
('_'),
('\_'),
('\\_'),
('\\\_'),
('\\\\_'),
('%'),
('\%'),
('\\%'),
('\\\%'),
('\\\\%')
;
SELECT p, hex(a) FROM t1;
p hex(a)
1 5C5C
2 5C6E
3 5C62
4 5C72
5 5C74
6 5C78
7 5C61
8 5C6161
9 5C5C61
10 5C5C6161
11 5F
12 5C5F
13 5C5C5F
14 5C5C5C5F
15 5C5C5C5C5F
16 25
17 5C25
18 5C5C25
19 5C5C5C25
20 5C5C5C5C25
delete from t1 where a in ('\n','\r','\t', '\b');
select
masks.p,
masks.a as mask,
examples.a as example
from
t1 as masks
left join t1 as examples on examples.a LIKE masks.a
order by masks.p, example;
p mask example
1 \\ \\
6 \x \x
7 \a \a
8 \aa \aa
9 \\a \\a
10 \\aa \\aa
11 _ %
11 _ _
12 \_ \%
12 \_ \a
12 \_ \x
12 \_ \\
12 \_ \_
13 \\_ \\%
13 \\_ \\a
13 \\_ \\_
14 \\\_ \\\%
14 \\\_ \\\_
15 \\\\_ \\\\%
15 \\\\_ \\\\_
16 % %
16 % \%
16 % \a
16 % \aa
16 % \x
16 % \\
16 % \\%
16 % \\a
16 % \\aa
16 % \\\%
16 % \\\\%
16 % \\\\_
16 % \\\_
16 % \\_
16 % \_
16 % _
17 \% \%
17 \% \a
17 \% \aa
17 \% \x
17 \% \\
17 \% \\%
17 \% \\a
17 \% \\aa
17 \% \\\%
17 \% \\\\%
17 \% \\\\_
17 \% \\\_
17 \% \\_
17 \% \_
18 \\% \\
18 \\% \\%
18 \\% \\a
18 \\% \\aa
18 \\% \\\%
18 \\% \\\\%
18 \\% \\\\_
18 \\% \\\_
18 \\% \\_
19 \\\% \\\%
19 \\\% \\\\%
19 \\\% \\\\_
19 \\\% \\\_
20 \\\\% \\\\%
20 \\\\% \\\\_
DROP TABLE t1;
SET @@SQL_MODE='NO_BACKSLASH_ESCAPES';
SELECT 'a\\b', 'a\\\"b', 'a''\\b', 'a''\\\"b';
a\\b a\\\"b a'\\b a'\\\"b
a\\b a\\\"b a'\\b a'\\\"b
SELECT "a\\b", "a\\\'b", "a""\\b", "a""\\\'b";
a\\b a\\\'b a"\\b a"\\\'b
a\\b a\\\'b a"\\b a"\\\'b
SET @@SQL_MODE='';
SELECT 'a\\b', 'a\\\"b', 'a''\\b', 'a''\\\"b';
a\b a\"b a'\b a'\"b
a\b a\"b a'\b a'\"b
SELECT "a\\b", "a\\\'b", "a""\\b", "a""\\\'b";
a\b a\'b a"\b a"\'b
a\b a\'b a"\b a"\'b
SET @@SQL_MODE='';
create function `foo` () returns int return 5;
show create function `foo`;
Function sql_mode Create Function character_set_client collation_connection Database Collation
foo CREATE DEFINER=`root`@`localhost` FUNCTION `foo`() RETURNS int(11)
return 5 latin1 latin1_swedish_ci latin1_swedish_ci
SET @@SQL_MODE='ANSI_QUOTES';
show create function `foo`;
Function sql_mode Create Function character_set_client collation_connection Database Collation
foo CREATE DEFINER=`root`@`localhost` FUNCTION `foo`() RETURNS int(11)
return 5 latin1 latin1_swedish_ci latin1_swedish_ci
drop function `foo`;
create function `foo` () returns int return 5;
show create function `foo`;
Function sql_mode Create Function character_set_client collation_connection Database Collation
foo ANSI_QUOTES CREATE DEFINER="root"@"localhost" FUNCTION "foo"() RETURNS int(11)
return 5 latin1 latin1_swedish_ci latin1_swedish_ci
SET @@SQL_MODE='';
show create function `foo`;
Function sql_mode Create Function character_set_client collation_connection Database Collation
foo ANSI_QUOTES CREATE DEFINER="root"@"localhost" FUNCTION "foo"() RETURNS int(11)
return 5 latin1 latin1_swedish_ci latin1_swedish_ci
drop function `foo`;
SET @@SQL_MODE='';
create table t1 (a int);
create table t2 (a int);
create view v1 as select a from t1;
show create view v1;
View Create View character_set_client collation_connection
v1 CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`a` AS `a` from `t1` latin1 latin1_swedish_ci
SET @@SQL_MODE='ANSI_QUOTES';
show create view v1;
View Create View character_set_client collation_connection
v1 CREATE ALGORITHM=UNDEFINED DEFINER="root"@"localhost" SQL SECURITY DEFINER VIEW "v1" AS select "t1"."a" AS "a" from "t1" latin1 latin1_swedish_ci
create view v2 as select a from t2 where a in (select a from v1);
drop view v2, v1;
drop table t1, t2;
select @@sql_mode;
@@sql_mode
ANSI_QUOTES
set sql_mode=2097152;
select @@sql_mode;
@@sql_mode
STRICT_TRANS_TABLES
set sql_mode=4194304;
select @@sql_mode;
@@sql_mode
STRICT_ALL_TABLES
set sql_mode=16384+(65536*4);
select @@sql_mode;
@@sql_mode
REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,NO_TABLE_OPTIONS,ANSI
set sql_mode=2147483648*2;
ERROR 42000: Variable 'sql_mode' can't be set to the value of '4294967296'
select @@sql_mode;
@@sql_mode
REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,NO_TABLE_OPTIONS,ANSI
set sql_mode=PAD_CHAR_TO_FULL_LENGTH;
create table t1 (a int auto_increment primary key, b char(5));
insert into t1 (b) values('a'),('b\t'),('c ');
select concat('x',b,'x') from t1;
concat('x',b,'x')
xa x
xb x
xc x
set sql_mode=0;
select concat('x',b,'x') from t1;
concat('x',b,'x')
xax
xb x
xcx
drop table t1;
SET @@SQL_MODE=@OLD_SQL_MODE;