文档介绍:Mysql三大列类型数值型整型Tinyint、Smallint、Mediumint、Int、Bigint小数型Float(D,M),Decimal(D,M)字符串型Char(M)Varchar(M),建表时既能足够存放,又不浪费空间。即:(1).占据空间(2).存储范围Tinyint微小的列类型,1字节类型字节最小值最大值(带符号/无符号)(带符号/无符号)Tinyint1-1281270255Smallint2-3276832767065535Mediumint3-2A232A23-102A24-1Int4-2A312A31-102A32-1Bigint8-2A632A63-102A64-1通过占用字节和所存范围分关系合理的选择类型例:Tinyintmgdq|l> table->idintprimarykeyauto_increments->nameuarchar(10)P->agetinyintjcharset=utfS;QueryOK,Growsaffected(0J6"匚)y$C|l>insertintotestfname^age)ualu&sC张三「J200');ueryOK,1rowaffected,1warning()ysql> select 羡 fromt@^t; + + 十id I name I age I + + +I张三 丨 25II永三 I127Irowsinset()insertinto(name,ago)ualuosf1张三’「-129');OK,1rowaffected,1warning()select昶fromtest;id|name|age123三三三Bf-_d725I127I-128Iins&t(,Tinyint的默认为有符号-128~127之间,当越界时自动取相应的边界值。若要存0~255无符号时:列的可选属性:Tinyint(M):宽度(在0填充的时候才有意义)Unsigned:无符号类型(非负),影响存储范围Zerofill: 0填充(默认无符号)myGql>altertableto«taddage3tinyint(5)zorofill;QueryOK,8rowsaffected()Recordsi£Duplicate:0Ul呂rnings:0♦ ■•・・1Field1Type1Null-------1Key1Default1id11NO1PRI1NULL1name1uarchar(ie)1VES11NULL1age1tinyint(M)1YES11NULL1ag«i1tinyint(3)unsignod1YES11NULL1仔21tinyint(1)1VES11NULL1age31tinyint(5)unsignedzerofill1YES11NULLmycql>tect:Extraauto^incr^m©ntI6row$inset(»c)叫sql>insertintotest(name9age1)ualues(e张三*,*2O0e);QueryOK,1rowaffected()叫insertintotest(name,age1)ualues(a李四",*-100-);QueryOK,1rowaffected,1warning()mysql>select芙Fromtest;IidInameIageIage1I亠 亠 丄 丄 亠I 1 I 5-121?1 3 1孚1 4 1子1 5 1 31 G 1子1 7 1 2 -r -y -r《三 1 25 1 NULL 1匕三 1 127 I NULL I£三 1 I NULL 1夂三 1 127 | NULL |E四 1 -100 I NULL I长三 1 NULL 1 200 1巨四 1 NULL 1 0 1丄 丄F T T T-7rowsinset()1>insertintotest->(name,age3)->ualu&s->「赵六'/S');uQIC,1rowaff©et&d()箕fromt&st;id I nameI ageI agelI age2I age3I卜 + + + + + +12345G789一一一一张张张张李张李王制LLuNiNULLLLuNLLJNINULLNULLLLuN三四三四五六60JINULLNULLINULLILLuNNULL| 2G0|NULL|NULL!NULLI0INULLINULL|NULLIN