SQL Select 语句的用法

Posted 2023-03-13

参考技术A 以下是代码片段：
SQL:
select
*
into
b
from
a
where
1<>1说明：拷贝表(拷贝数据,源表名：a
目标表名：b)以下是代码片段：
SQL:
insert
into
b(a,
b,
c)
select
d,e,f
from
b;说明：显示文章、提交人和最后回复时间以下是代码片段：
SQL:
select
a.title,a.username,b.adddate
from
table
a,(select
max(adddate)
adddate
from
table
where
table.title=a.title)
b说明：外连接查询(表名1：a
表名2：b)以下是代码片段：
SQL:
select
a.a,
a.b,
a.c,
b.c,
b.d,
b.f
from
a
LEFT
OUT
JOIN
b
ON
a.a
=
b.c说明：日程安排提前五分钟提醒以下是代码片段：
SQL:
select
*
from
日程安排
where
datediff(’minute’,f开始时间,getdate())>5
说明：两张关联表，删除主表中已经在副表中没有的信息
SQL:
以下是代码片段：
delete
from
info
where
not
exists
(
select
*
from
infobz
where
info.infid=infobz.infid 说明：--
SQL:
以下是代码片段：
SELECT
A.NUM,
A.NAME,
B.UPD_DATE,
B.PREV_UPD_DATE

FROM
TABLE1,

(SELECT
X.NUM,
X.UPD_DATE,
Y.UPD_DATE
PREV_UPD_DATE

FROM
(SELECT
NUM,
UPD_DATE,
INBOUND_QTY,
STOCK_ONHAND

FROM
TABLE2

WHERE
TO_CHAR(UPD_DATE,’YYYY/MM’)
=
TO_CHAR(SYSDATE,
’YYYY/MM’))
X,

(SELECT
NUM,
UPD_DATE,
STOCK_ONHAND

FROM
TABLE2

WHERE
TO_CHAR(UPD_DATE,’YYYY/MM’)
=

TO_CHAR(TO_DATE(TO_CHAR(SYSDATE,
’YYYY/MM’)
¦¦
’/01’,’YYYY/MM/DD’)
-
1,
’YYYY/MM’)
Y,

WHERE
X.NUM
=
Y.NUM
（+）

AND
X.INBOUND_QTY
+
NVL(Y.STOCK_ONHAND,0)
<>
X.STOCK_ONHAND
B
WHERE
A.NUM
=
B.NUM说明：--
SQL:
以下是代码片段：
select
*
from
studentinfo
where
not
exists(select
*
from
student
where
studentinfo.id=student.id)
and
系名称=’"&strdepartmentname&"’
and
专业名称=’"&strprofessionname&"’
order
by
性别,生源地,高考总成绩说明：
从数据库中去一年的各单位电话费统计(电话费定额贺电化肥清单两个表来源）
SQL:
以下是代码片段：
SELECT
a.userper,
a.tel,
a.standfee,
TO_CHAR(a.telfeedate,
’yyyy’)
AS
telyear,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’01’,
a.factration))
AS
JAN,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’02’,
a.factration))
AS
FRI,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’03’,
a.factration))
AS
MAR,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’04’,
a.factration))
AS
APR,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’05’,
a.factration))
AS
MAY,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’06’,
a.factration))
AS
JUE,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’07’,
a.factration))
AS
JUL,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’08’,
a.factration))
AS
AGU,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’09’,
a.factration))
AS
SEP,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’10’,
a.factration))
AS
OCT,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’11’,
a.factration))
AS
NOV,

SUM(decode(TO_CHAR(a.telfeedate,
’mm’),
’12’,
a.factration))
AS
DEC
FROM
(SELECT
a.userper,
a.tel,
a.standfee,
b.telfeedate,
b.factration

FROM
TELFEESTAND
a,
TELFEE
b

WHERE
a.tel
=
b.telfax)
a
GROUP
BY
a.userper,
a.tel,
a.standfee,
TO_CHAR(a.telfeedate,
’yyyy’)说明：四表联查问题：SQL:
以下是代码片段：
select
*
from
a
left
inner
join
b
on
a.a=b.b
right
inner
join
c
on
a.a=c.c
inner
join
d
on
a.a=d.d
where
.....说明：得到表中最小的未使用的ID号
SQL:
以下是代码片段：
SELECT
(CASE
WHEN
EXISTS(SELECT
*
FROM
Handle
b
WHERE
b.HandleID
=
1)
THEN
MIN(HandleID)
+
1
ELSE
1
END)
as
HandleID
FROM
Handle
WHERE
NOT
HandleID
IN
(SELECT
a.HandleID
-
1
FROM
Handle
a)