存储过程语法异常 帮忙看下 小妹是菜鸟

存储过程语法错误 大虾帮忙看下 小妹是初学者
if l_date=8 then ( if timeoffset=0 then let tmp_sjdm=F_GET_SJDM(proddate,0);
  elif timeoffset=1 then (let tmp_date = to_char((date(substr('proddate',5,2)||'/01/'||substr('proddate',1,4))- 1 ),'%Y%m%d');
  let tmp_sjdm= F_GET_SJDM(tmp_date,0);
  )  
  elif timeoffset=2 then (let tmp_date = to_char((date(substr('proddate',5,2)||substr('proddate',7,2)||substr('proddate',1,4))- 1 UNITS YEAR),'%Y%m%d');
  let tmp_sjdm= F_GET_SJDM(tmp_date,0);
  ) 
  elif timeoffset=3 then (let tmp_date = to_char((date('01/01/'||substr('proddate',1,4))- 1 ),'%Y%m%d');
  let tmp_sjdm= F_GET_SJDM(tmp_date,0);
  )
  end if;
  )
  elif l_date=7 then (if timeoffset=0 then let tmp_sjdm=F_GET_SJDM(proddate,1);
  elif timeoffset=1 then (let tmp_date = to_char((date(substr('proddate',5,2)||'/01/'||substr('proddate',1,4))- 1 ),'%Y%m')||'3';
  let tmp_sjdm= F_GET_SJDM(tmp_date,1);
  )  
  elif timeoffset=2 then (let tmp_date = to_char((date(substr('proddate',5,2)||'/01/'||substr('proddate',1,4))- 1 UNITS YEAR),'%Y%m')||'3';
  let tmp_sjdm= F_GET_SJDM(tmp_date,1);
  ) 
  elif timeoffset=3 then (let tmp_date = to_char((date('01/01/'||substr('proddate',1,4))- 1 ),'%Y')||'123';
  let tmp_sjdm= F_GET_SJDM(tmp_date,1);
  )
  end if;
  )
  elif l_date=6 then (if timeoffset=0 then let tmp_sjdm=F_GET_SJDM(proddate,2);
  elif timeoffset=1 then (let tmp_date = to_char((date(substr('proddate',5,2)||'/01/'||substr('proddate',1,4))- 1 ),'%Y%m');
  let tmp_sjdm= F_GET_SJDM(tmp_date,2);
  )  
  elif timeoffset=2 then (let tmp_date = to_char((date(substr('proddate',5,2)||'/01/'||substr('proddate',1,4))- 1 UNITS YEAR),'%Y%m');
  let tmp_sjdm= F_GET_SJDM(tmp_date,2);
  ) 
  elif timeoffset=3 then (let tmp_date = to_char((date('01/01/'||substr('proddate',1,4))- 1 ),'%Y')||'12';
  let tmp_sjdm= F_GET_SJDM(tmp_date,2);
  )
  end if;
  )
  elif l_date=5 then (if timeoffset=0 then let tmp_sjdm=F_GET_SJDM(proddate,3);
  elif timeoffset=1 then (
  let tmp_sjdm= F_GET_SJDM(tmp_date,3)-1;
  )  
  elif timeoffset=2 then (let tmp_date = to_char((date('01/01/'||substr('proddate',1,4))- 1 ),'%Y')||substr('proddate',5,1);
  let tmp_sjdm= F_GET_SJDM(tmp_date,3);
  ) 
  elif timeoffset=3 then (let tmp_date = to_char((date('01/01/'||substr('proddate',1,4))- 1 ),'%Y')||'4';