3 ^4 q, A) x- a3 \+ J1 G Address 3 ]! U v5 y6 F6 F
# ^+ A7 J( ?. w
City @3 @9 q: l$ `9 o ; c; {- r) K# t. y3 a! l
% B5 I0 m, ~1 k
Pettersen " }- ` b) d# Z/ A6 l5 N% A+ {: C' C
/ H# P" }0 t+ |, d: G9 k
Kari ; F) X1 O# M: Y' f& D 1 ~ Y8 s+ Y, E/ K; m/ s
Storgt 20 & W+ N3 K% C' D2 F$ ^+ r
y) x1 e5 D! e9 G; k$ l Stavanger 0 V7 I" b! |3 Z" y2 x
$ T. l) b1 e+ s7 O
</P><>运行下面的SQL插入一行数据:</P><>INSERT INTO Persons 5 j; D1 J0 d j4 P- a1 `) N; q+ jVALUES ('Hetland', 'Camilla', 'Hagabakka 24', 'Sandnes') ; z; E& |2 ^6 Z9 t4 z* Q
: e3 o. O# m8 `) l2 C$ R6 D例: / @, J( t6 G; m! i8 `2 r: l# W </P><>"erson"表中的原始数据: ) v+ L& T- i* ?5 I. P4 [) c& @1 m1 }" Y# r </P><>LastName x! X9 q$ m2 d O
4 u( @1 g! [; E5 ]. M( h
FirstName ) B: ?0 p$ E' i1 R6 T m " x6 g# \9 [( S6 z/ T Address + c& E, f% R) v3 E ) I; ^# y2 |$ n i8 K* L
City . ^" ?$ i+ E. C* P1 O C
3 S r6 W+ J K( t+ V 8 ^/ N% A$ F8 h2 x- p( N* @Nilsen ) a3 m" W: x- |9 L. [! S+ R " p/ l! E3 L9 ?5 n& a
Fred + t& a& j/ l+ m* n: }: h0 a % n# s# `. _3 S o. q: `. l$ S Kirkegt 56 6 }+ f& c/ c- ~' h # a! n) Y& X5 p6 b6 n Y: u/ }
Stavanger ' Z1 r0 t" _. v- o: h4 b % y3 S+ w/ u8 a3 y1 `: u) b6 X3 Z
/ A" T0 Z2 V- E W
Rasmussen 7 ` D1 d) j& m. h6 Z" g* L# H ' D k4 ? G% r
7 }, a6 M0 R, j/ u c5 x5 I
2 C- t1 |. I8 }. ~; V/ Y
Storgt 67 }8 G$ {3 A3 q( t
$ d' Q8 s q/ X! k" w# d- n
% P* m5 b: K1 E% G' X5 d
, \# T5 @- R# s" k& j
</P><>运行下面的SQL将Person表中LastName字段为"Rasmussen"的FirstName更新为"Nina":</P><>UPDATE Person SET FirstName = 'Nina' ! ]9 b7 j% U! t9 v) C
WHERE LastName = 'Rasmussen' $ h+ u" Y' \# b/ L) m4 o9 v : _/ o' ~- M; m! _' Q7 t) @更新后"erson"表中的数据为: 8 \1 A/ {* T$ a1 F" h5 z, K
</P><>LastName $ P1 g( W8 U3 |; d/ E
3 {0 B1 R) G! x7 W' {1 ]! D
FirstName 2 l4 N( `8 ]4 G7 u
- J+ O+ \9 U4 O( ~. H
Address ) c, X' q _) h! j" y1 `; o# S. o " o3 D% _7 G, F1 Y4 B+ [9 A1 [( `
City $ P( D! n& Z0 i8 X. M! a 5 l% ]; p% ?8 Q8 \ D& Y1 `3 i$ E& Y
7 t# a8 _) r' U2 n
Nilsen - n, F. v4 @$ P5 F8 M ; h' n4 N. U& z, j2 Y( S4 [
Fred 3 M7 D+ d% k, L7 V8 |0 q' Q - \; T) t9 e, C) Y/ S, x Kirkegt 56 . ^& O$ N' m( S6 y3 j, D
1 i( P% o+ ]) C# ^& ` Stavanger 2 B2 S& ~$ u- d! t1 G! [$ h 4 |5 b: ~ a G2 B2 M % n) K* `' y# F0 G" A; O6 h
Rasmussen 7 ]& A1 Q; F a( x
3 {8 p% \. `3 v
Nina $ z4 E4 {# p8 C/ e. {$ ]8 W : O/ O6 ~8 v9 G
Storgt 67 8 w! l, h* h0 g1 n* o6 m6 M5 @
O( V% b9 `5 I ; k& f$ g' A! n+ G
2 C1 l' k" j" J </P><>同样的,用UPDATE语句也可以同时更新多个字段:</P><>UPDATE Person 1 L' D( E X) O( _+ x4 MSET Address = 'Stien 12', City = 'Stavanger' % x p- t% B) A, E2 c0 ]/ O1 ^+ z
WHERE LastName = 'Rasmussen' 5 J# M/ m, o" g5 f; O2 t1 g5 d# C
</P><>更新后"erson"表中的数据为:</P><>LastName * F; g K$ D7 k# E' z, x , K v3 F) O3 D
FirstName 4 D% Q5 m( |, i5 ~- r8 U T
. r4 }$ Z* W, g) t Address # J3 X7 A' H7 [5 \, a7 y
# w+ i4 G7 I7 D) e City & K% L- m! _ R 1 h% P: i: w7 U# i, {! ^# o( _
! p k a/ W* j" j% C( Y. tNilsen 9 I, H2 W: B/ ^4 b- Z+ ] * P- X6 Z( H) S- H5 I
Fred : f+ B5 z: j. D/ n
/ ~: v) M n5 O4 g
Kirkegt 56 " U1 d/ k+ y1 M0 g" L
- O& E/ M( E6 f
Stavanger . ~. i9 x. z' K2 d( o! L( W, x
2 l3 s h$ H" s5 J4 } ' d5 f3 a f9 [" B6 K9 u' [3 N BRasmussen 1 n4 q& ~* h1 v2 {# ^
7 s% I; Y* c. R! S
Nina . s9 Q1 s( M- ^( _
$ L& A7 r0 w/ }9 y' }
Stien 12 # q3 S0 H0 k: M [" b+ R, R! p $ J' q- X6 k- T3 o! B Stavanger 1 ^) ~- ?0 E- |+ ^</P>
<>Delete3 {" w0 b( l0 g8 Y2 e6 |) z
用途: ) A! g+ J) A3 Q* x2 G
</P><> 删除表中的数据</P><>语法: - Z$ C1 F; v& S6 \$ r3 p) a! d
</P><>DELETE FROM table_name WHERE column_name = some_value 6 ^* H3 y. a" N' T 5 M# I& ]9 \! o6 G例: 6 k3 z# k/ ^1 q5 ^ </P><>"erson"表中的原始数据: 3 d9 I' p% \+ H+ u5 F$ L
</P><>LastName 0 E/ E- X' i% l + B! H+ Y* S# e2 [
FirstName 4 t. ~8 U' e2 [: e" G1 Y / r! q7 w1 V$ H0 M Address : u' F( e& ?- W2 F) |
6 O, X3 H6 ?& K5 J
City , M$ S; G7 T j
7 e( ]/ E& O0 p6 @! ~+ X
4 Q' e6 [6 y) ]8 F8 e. b( Q
Nilsen + p6 J! p* e% P# f8 b T+ u' F
% b+ J7 ]0 n) t' c/ l0 s
Fred - d% R7 C9 n9 h$ h3 }: C6 R5 H( ^
& d: q$ A! G- x- ? Kirkegt 56 3 _' B; ^* r: Q( \ S, u) C + f, t6 D; A1 ^& M1 W- q Stavanger 0 Q6 X9 ~2 R5 G5 d9 ~' x' r + }9 c$ _- N! h : y, z, ^" C, t1 rRasmussen : ?" q* A( r/ ]# Z ?# r- d 5 W! ]. N) C: K0 M Nina ) Z6 m4 l& Y, t5 I# o 6 o+ Z" l# c( Q" n( W
Stien 12 1 y1 ^& a# {: g D7 f* Q
0 |7 A. s$ n! S4 E. U Stavanger 8 s# M# c& t. r 0 _1 a6 c3 t [ r- s
</P><>删除Person表中LastName为"Rasmussen"的数据:</P><>DELETE FROM Person WHERE LastName = 'Rasmussen' - X: u! J% ]; X; B g0 n
1 Q6 F! W& {8 f5 g( f
执行删除语句后"erson"表中的数据为: 2 r& l, ?/ h b. N7 v, S. M
</P><>LastName 0 Y4 \2 d8 G/ g3 D! Z8 K
0 J, D- L- r1 `2 o; d4 @/ A
FirstName $ ?& x/ L2 j' `/ H0 b8 t
' X# J# N# G/ n/ S Address 2 A$ \+ H1 H. d; E
+ s; e6 T1 g G* m5 g& A+ {' b
City 0 U- P& O! h# d% P( P' Y" N + m. i# ~2 u; z) ~5 v; [- e y' O: k' h5 b. f d5 E' bNilsen 6 ~, e b' U* ~& E# \8 S" a 0 I* P9 J+ S2 I1 v$ z$ G Fred 3 v1 Y* A, [3 R7 |- A9 j * `; [1 S1 n+ f8 @$ h% L
Kirkegt 56 + U Y/ r! |9 a$ X& z: k ' k* O- U& x. p2 {2 i, ? Stavanger & }7 Q% _, i8 v0 w( N5 K
9 x* T4 [" M. `# D' c0 z: h- E
* a1 Z8 ]7 m. I/ Z, ^
<>Create Table0 A3 p r9 `" E3 H
用途: 7 A1 X) o; ]3 E( i' l& P1 z
</P><> 建立新的资料表。</P><>语法: ) J% [ f8 L4 ]7 l* N/ v% P </P><>CREATE TABLE table_name m+ O3 H7 @4 B3 q$ O( 1 E! q4 j j( d0 `% E
column_name1 data_type, 9 c, v+ t" {; `column_name2 data_type, 5 A, D0 @* _$ D
....... " D; m- m* p- t) " Y' U) Z5 R4 r8 H" v/ Y# \ ( \# T; `( R9 N& R例: 8 |& w" Q1 e- _0 `$ P6 [1 G w </P><>创建一张叫"erson"的表,该表有4个字段"LastName", "FirstName", "Address", "Age": 6 N! o$ p' m" O( C9 ^) `; H8 T ~
</P><>CREATE TABLE Person ( R' ?4 |0 q0 J8 s1 g- [, Z. ~
( 5 _( N4 D. M) V
LastName varchar, 5 m' G- h: P$ g( j$ h
FirstName varchar, 9 \, b% w- ~9 g: c- S
Address varchar, 7 E3 u6 V+ a- I8 x% ^Age int # `) a' t8 B' s: o2 `1 D) + @0 u3 h7 R" D6 w9 H4 b C </P><>如果想指定字段的最大存储长度,你可以这样:</P><>CREATE TABLE Person . Q$ _5 c, ]8 C8 a, D
( ) G& W; Q0 Q( R* e' M0 J
LastName varchar(30), 8 r; {$ r0 }2 S5 U" T! l
FirstName varchar(30), 2 f: n: G; @! H: xAddress varchar(120), 7 ]) ^9 @ I& _: y" o4 W
Age int(3) 0 F! ?% L6 E. W" m7 |8 f
) 5 @* X. n9 e( K$ O2 T( f </P><>下表中列出了在SQL的一些数据类型:</P><>Data Type h+ r2 u% O& t- X4 s( |# B * [( Q1 [2 H, P8 f! a% M
Description 0 h% N8 P4 U9 D4 | 6 e' L$ D, {8 t: ~6 O% r1 K
B# V! W% h% ^8 pinteger(size) $ e( {+ d0 u3 v7 Z y, Cint(size)9 K4 \- I! q- v& z& w8 e
smallint(size) ! [. R! y. F9 ytinyint(size) & N$ h, \, ^& N/ y5 h% @
# B# d& j( W) @0 B* T
Hold integers only. The maximum number of digits are specified in parenthesis. 6 \% `& | }6 ?/ }6 y% ^ ; K, c) [" P' ^7 b ! B0 K1 p4 M: a0 Q
decimal(size,d) 6 n1 a- L8 U, Qnumeric(size,d) ' @5 B% ^3 k) O% y3 v: @2 K
* Z2 T2 }! ^9 l7 `' Y& z* M Hold numbers with fractions. The maximum number of digits are specified in "size". The maximum number of digits to the right of the decimal is specified in "d". " a7 Y5 R7 |/ E2 } g: J
4 p# ?3 ]7 u; {6 o ) v8 g- e! p5 u( a: ?7 J
char(size) 0 U8 [5 F3 g3 p8 z! S5 ] 9 g$ {* W9 M3 K) G+ y
Holds a fixed length string (can contain letters, numbers, and special characters). The fixed size is specified in parenthesis. : D. M7 h" b5 m & T- c% R2 }* \4 H# y3 l K 7 G# j+ [4 v6 Z% D9 J/ Z! Gvarchar(size) & c) ^1 R/ b; E$ C 6 f- y! D% q- ?7 ~/ n/ D Holds a variable length string (can contain letters, numbers, and special characters). The maximum size is specified in parenthesis. 6 j/ J Z1 T; Z% }/ H1 i2 w& B
/ M+ X# L% M4 E: w
$ p3 O# Z$ m7 f6 y6 K4 t) O
date(yyyymmdd) + S6 d- f' `9 A: ^& J, `
3 W" E9 V2 a* O& _) X
Holds a date 9 k3 u9 |" Y, N \% T
. n* O ]1 Q- }" t3 Y& o
1 S, \/ z; l1 g( m2 c + X7 W' ~% ` D% p& x. K5 c/ r </P><> 7 {- \9 `$ H1 s+ |+ N3 z
</P><>Alter Table r% H( q$ \$ v
用途: : ^2 Z" ?- [5 b
</P><> 在已经存在的表中增加后者移除字段</P><>语法: " h9 x( L) P9 r# u
</P><>ALTER TABLE table_name ' A; N/ r v8 t; S5 w
ADD column_name datatype </P>
<>Alter Table! q" C& k% |. ]# S2 b" M1 Z/ Q
用途: / e6 S4 M# O6 ?
</P><> 在已经存在的表中增加后者移除字段</P><>语法: + U( v9 C0 L* T6 e- r </P><>ALTER TABLE table_name , k d, o7 Z$ |- W; @; Q$ y
ADD column_name datatype / N# f! B G6 U9 r! T8 |* o; P
ALTER TABLE table_name * \; B' l. E7 o- F- u4 k9 p0 vDROP COLUMN column_name # p& P; [8 C* t' N9 r + o' ?$ X& i* C1 |5 B
注意:某些数据库管理系统不允许移除表中的字段 . g q9 ?8 ~" i+ f- y, C
</P><> 0 {" U5 z9 ?' Z- z3 V
</P><>例: 9 A: j3 `1 m" `- A9 z& s
</P><>"erson"表中的原始数据: : c6 ~1 v* l# k
</P><>LastName * `; ~7 v4 B, y5 T; Q- V( ^
! s! t, B# b! @: a2 S ` FirstName . {0 u- _2 D. q9 x- G2 L
$ A6 b3 O6 u& p# B! A Address + W/ B/ ~/ j$ Z% U+ y# n
, L" s( i9 P7 j/ U! W6 ?5 G
, y2 N; l' z! A0 KPettersen ! M# t( W X2 i ; s$ b3 X7 [9 t3 y' Q6 K Kari ; q8 G. o3 O* u$ Q [
4 g9 m+ ?. {4 f Storgt 20 6 I0 g! Y/ P2 | ^8 R g% \; }* t* B, i- G/ `- }4 N , ?6 P; A. }7 H" n0 X2 {$ b1 G
; A9 I- A9 r8 _( C' U/ w
</P><>在Person表中增加一个名为City的字段:</P><>ALTER TABLE Person ADD City varchar(30) # u# ^8 S s1 u# m+ N' r( k
</P><>增加后表中数据如下:</P><>LastName - S0 }# e1 M4 |* k0 n3 B
% v% L4 ]) z# {- @8 d FirstName ' O' j2 h0 }9 v% |) t5 J . K- I+ s. W/ V- e
Address 6 R+ @6 f* ]$ L. e# w W ) X1 i+ c1 C `( O, c City 3 S! J' A5 K8 U2 z1 t+ o 3 R l5 \: h4 q V" A
. Y8 K5 {! a4 J6 `4 |2 ~2 QPettersen * _7 K! N2 N5 X+ l% z `& M# U1 M. Y5 A9 z
Kari , }% r" u& P2 t 4 F4 c8 k" O& s3 s Storgt 20 7 h% r2 i* w6 P3 c
7 j6 D, c% v# s 8 Y6 h8 n" J3 l# w3 p0 J 2 R& c/ C9 b5 u Y9 G G
. q$ a) p+ l2 m
* l$ b/ V0 {* ]/ K& ?. f, t% m
</P><>移除Person表中原有的Address字段:</P><>ALTER TABLE Person DROP COLUMN Address - b1 Q. c `# L) j
</P><>移除后表中数据如下:</P><>LastName 8 ? W" v& {- q) q% m3 E ) N, T& `% l5 _, b: ] U
FirstName % N: U6 f9 D7 X 5 @6 C% S3 _/ [( b8 w, n% P5 p
City 6 G$ a0 b$ `; g8 M2 N8 \: o - C' l$ l0 A) a
/ ?: e3 i5 W. l: I
Pettersen + B/ o$ C- a5 Z& K# P4 A" y
) D0 ?0 F" r9 t: y Kari , g) \; u* H! G7 }' ?
</P>