1
|
create
database
db1;
|
1
|
create
database
db2
character
set
gbk;
|
1
|
create
database
db3
character
set
utf8
collate
utf8_bin;
|
1
|
show databases;
|
1
|
show
create
database
数据库名;
|
1
|
select
database
();
|
1
2
3
4
5
6
7
8
|
create
table
employee(
eid
int
primary
key
auto_increment,
ename
varchar
(20)
not
null
,
email
varchar
(30)
unique
,
birthday
date
,
job
varchar
(20),
resume text
);
|
1
|
alter
table
employee
add
image
varchar
(50);
|
1
|
alter
table
employee
drop
job;
|
1
|
alter
table
employee
modify
image
varchar
(80)
not
null
;
|
1
|
alter
table
employee change image eimage
varchar
(60);
|
1
|
rename
table
employee
to
user
;
|
1
|
[
size
=3]a[/
size
]lter
table
user
character
set
gbk;
|
1
|
|
1
|
insert
into
employee
values
(
null
,
'bbb'
,
'[email protected]'
,
'1990-09-01'
,
'HR'
,
'I am HR'
);
|
1
|
|
1
|
show variables like
'%character%'
;
|
1
|
services.msc
|
1
|
update
employee
set
job=
'WORKER'
;
|
1
|
|
1
|
|
1
|
delete
from
employee
where
eid = 8;
|
1
|
delete
from
employee;
|
1
2
3
4
5
6
7
|
create
table
exam(
id
int
primary
key
auto_increment,
name
varchar
(20),
english
int
,
chinese
int
,
math
int
);
|
1
2
3
4
5
6
|
insert
into
exam
values
(
null
,
'张三'
,85,74,91);
insert
into
exam
values
(
null
,
'李四'
,95,90,83);
insert
into
exam
values
(
null
,
'王五'
,85,84,59);
insert
into
exam
values
(
null
,
'赵六'
,75,79,76);
insert
into
exam
values
(
null
,
'田七'
,69,63,98);
insert
into
exam
values
(
null
,
'李四'
,89,90,83);
|
1
|
select
*
from
exam;
|
1
|
select
name
,english
from
exam;
|
1
|
select
distinct
english
from
exam;
|
1
|
select
*
from
exam
where
name
=
'李四'
;
|
1
|
elect *
from
exam
where
name
=
'李四'
and
english >90;
|
1
|
select
name
,english+10,chinese+10 ,math+10
from
exam;
|
1
|
select
name
,english+chinese+math
from
exam;
|
1
|
select
name
, english+chinese+math
as
sum
from
exam;
|
1
|
select
*
from
exam
order
by
chinese;
|
1
|
elect *
from
exam
order
by
chinese
desc
;
|
1
|
elect *
from
exam
order
by
english
desc
, chinese
desc
;
|
1
|
select
*
from
exam
where
name
like
'李%'
order
by
english
asc
;
|
1
|
select
name
,(english+chinese+math)
from
exam;
|
1
2
|
select
sum
(english+chinese+math)
from
exam;
-- ifnull(english,0)
select
sum
(english)+
sum
(chinese)+
sum
(math)
from
exam;
|
1
|
select
count
(*)
from
exam;
|
1
|
select
max
(english)
from
exam;
|
1
|
select
min
(chinese)
from
exam;
|
1
|
select
avg
(english)
from
exam;
|
1
|
SELECT
product,
COUNT
(*)
FROM
orderitem
GROUP
BY
product;
|
1
|
SELECT
product,
SUM
(price)
FROM
orderitem
GROUP
BY
product;
|
1
|
[
size
=3]S[/
size
]ELECT product,
SUM
(price)
FROM
orderitem
GROUP
BY
product
HAVING
SUM
(price) > 2000;
|
1
|
SELECT
product,
SUM
(price)
FROM
orderitem
WHERE
product
LIKE
'电%'
GROUP
BY
product
HAVING
SUM
(price) > 1500
ORDER
BY
SUM
(price)
DESC
;
|
1
2
3
4
|
create
table
customer(
cid
int
primary
key
auto_increment,
cname
varchar
(20)
);
|
1
2
3
4
5
|
create
table
orders(
oid
int
primary
key
auto_increment,
addr
varchar
(50),
cid
int
);
|
1
|
alter
table
orders
add
foreign
key
(cid)
references
customer(cid);
|
1
|
SELECT
*
FROM
customer c
INNER
JOIN
orders o
ON
c.cid = o.cid;
|
1
|
SELECT
*
FROM
customer c ,orders o
WHERE
c.cid = o.cid;
|
1
|
SELECT
*
FROM
customer c
LEFT
OUTER
JOIN
orders o
ON
c.cid = o.cid;
|
1
|
SELECT
*
FROM
customer c
RIGHT
OUTER
JOIN
orders o
ON
c.cid = o.cid;
|
1
|
SELECT
*
FROM
customer c,orders o
WHERE
c.cid = o.cid
AND
c.cid
IN
(
SELECT
cid
FROM
orders
WHERE
addr
LIKE
'海淀%'
);
|
1
|
SELECT
c.cname,
COUNT
(*)
FROM
customer c,orders o
WHERE
c.cid = o.cid
GROUP
BY
c.cname;
|