存储过程 substr

create procedure substr (sText varchar(255), iFPos smallint, iLen
smallint)
returning varchar(255);

define i smallint;
define sReturn varchar(255);

if iFPos > 1 then
for i = 1 to iFPos - 1 step 1
let sText = sText[2,255];
end for;
end if;

let sReturn = sText[1,1];
if iLen > 1 then
let sText = sText[2,255];
for i = 2 to iLen step 1
let sReturn = sReturn ¦ ¦ sText[1,1];
let sText = sText[2,255];
end for;
end if;

return sReturn;

end procedure;