Date time type

 

Data Type	“Zero” Value
DATE	'0000-00-00'
TIME	'00:00:00'
DATETIME	'0000-00-00 00:00:00'
TIMESTAMP	'0000-00-00 00:00:00'
YEAR	0000

https://dev.mysql.com/doc/refman/8.0/en/date-and-time-types.html

Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT

 

Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT

MySQL supports the SQL standard integer types INTEGER (or INT) and SMALLINT. As an extension to the standard, MySQL also supports the integer types TINYINT, MEDIUMINT, and BIGINT. The following table shows the required storage and range for each integer type.

Table 13.1 Required Storage and Range for Integer Types Supported by MySQL

Type	Storage (Bytes)	Minimum Value Signed	Minimum Value Unsigned	Maximum Value Signed	Maximum Value Unsigned
TINYINT	1	-128	0	127	255
SMALLINT	2	-32768	0	32767	65535
MEDIUMINT	3	-8388608	0	8388607	16777215
INT	4	-2147483648	0	2147483647	4294967295
BIGINT	8	-263	0	263-1	264-1

MySQL ANY ALL IN

mysql> select  4 >any(select 33  as V UNION ALL select 11) as R;

+---+

| R |

+---+

| 0 |

+---+

1 row in set (0.00 sec)

mysql> select  34 >any(select 33  as V UNION ALL select 11) as R;

+---+

| R |

+---+

| 1 |

+---+

1 row in set (0.01 sec)

-----------

ALL

mysql> select  34 >ALL(select 33  as V UNION ALL select 11) as R;

+---+

| R |

+---+

| 1 |

+---+

1 row in set (0.00 sec)

https://dev.mysql.com/doc/refman/8.4/en/any-in-some-subqueries.html

Syntax:

operand comparison_operator ANY (subquery)
operand IN (subquery)
operand comparison_operator SOME (subquery)

Where comparison_operator is one of these operators:

=  >  <  >=  <=  <>  !=

MySQL exists

 select  exists  (select  'A' where 5>10) as R;

+---+

| R |

+---+

| 0 |

+---+

Because     the evaluated query return   empty set, if return any value doesn't matter the value   it will return  1, doesn't matter if is null or 0.

select  'A' where 5>10;

Empty set (0.00 sec)

------------------------    exists   here will return 1

select  exists  (select  NULL) as R;

+------+

| R    |

+------+

|    1 |

+------+

1 row in set (0.00 sec)

-

 select  exists  (select  0) as R;

+---+

| R |

+---+

| 1 |

+---+

select 'Ambiorix' where exists(select 1);

+----------+

| Ambiorix |

+----------+

| Ambiorix |

+----------+

MySQL IF

mysql> select if(10>8,'A','B') as result;

+--------+

| result |

+--------+

| A      |

+--------+

--------------

mysql> select if(10>15,'A','B') as result;

+--------+

| result |

+--------+

| B      |

+--------+

MySQL case

mysql> set @i=4;

 mysql> select case @i

    -> when @i>3 then'A'

    -> else 'B'

    -> end as t;

------------

mysql> select case

    -> when 5>4 then  'A'

    -> when 5<6 then 'B'

    -> else 'C'

    -> end as t;

+---+

Functions and Operators

  Functions and Operators

https://dev.mysql.com/doc/refman/8.4/en/functions.html

Data type

https://dev.mysql.com/doc/refman/8.4/en/data-types.html