点击后从一个表中读纪录作为新表的列，这段代码为啥不行？

string thiscolumn,sqlstatement,thisgzb,temp
integer i,endnumber

thisgzb="CREATE TABLE GZB0311"&
+"(序号 NUMBER(3) NOT NULL)"

execute immediate :thisgzb;

//从工资项目表中选取纪录
sqlstatement="SELECT * FROM 工资项目表"

PREPARE SQLSA FROM :sqlstatement;
DESCRIBE SQLSA INTO SQLDA;
DECLARE my_cursor DYNAMIC CURSOR FOR SQLSA;
OPEN DYNAMIC my_cursor USING DESCRIPTOR SQLDA;

endnumber=SQLDA.NumOutputs




for i=1 to endnumber
FETCH my_cursor USING DESCRIPTOR SQLDA;
thiscolumn=GetDynamicString(SQLDA,1)
temp="ALTER TABLE GZB0311 ADD(" +thiscolumn+"CHAR(50))"
execute immediate :temp;
next

CLOSE my_cursor;