% 代表0或多個字符
_ 代表單個字符
like_ _,表示兩個字符的串
%china%表示帶有china 子串的串
一個利用like的例子
create table prod(
id varchar2(10)primary key,
color varchar2(10),
amount number
)
insert into prod values('P001','紅',124);
insert into prod values('P002','黃',34);
insert into prod values('P003','紅',null);
insert into prod values('M004','藍',890);
insert into prod values('M005','白',14);
insert into prod values('P006','紅',345);
insert into prod values('L007','藍',23);
insert into prod values('L008','綠',323);
insert into prod values('P009','紫',234);
選出所有以P打頭的產品
select * from prod
where id like 'p%';