drop table if exists t1;
set sql_mode="MySQL40";
select @@sql_mode;
@@sql_mode
MYSQL40,HIGH_NOT_PRECEDENCE
set @@sql_mode="ANSI";
select @@sql_mode;
@@sql_mode
REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ANSI
SELECT 'A' || 'B';
'A' || 'B'
AB
CREATE TABLE t1 (id INT, id2 int);
SELECT id,NULL,1,1.1,'a' FROM t1 GROUP BY id;
id	NULL	1	1.1	a
SELECT id FROM t1 GROUP BY id2;
id
drop table t1;
SET @@SQL_MODE="";
CREATE TABLE t1 (i int auto_increment NOT NULL, PRIMARY KEY (i));
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`i`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
SET @@SQL_MODE="MYSQL323";
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`i`)
) TYPE=MyISAM
SET @@SQL_MODE="MYSQL40";
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`i`)
) TYPE=MyISAM
SET @@SQL_MODE="NO_FIELD_OPTIONS";
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` int(11) NOT NULL,
  PRIMARY KEY (`i`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1;