这个sql怎么写？ - Oracle / 开发

有 a1 b1 c1三段sql代码和一个变量data_date，当data_date='01'时，执行a1这一段代码,当data_date='02'时，执行b1这一段代码，当data_date='03'时，执行c1这一段代码,这个sql怎么写？

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SQL code:
CASE data_date
WHEN '1'
THEN EXECUTE IMMEDIATE a1;
WHEN '2'
THEN EXECUTE IMMEDIATE b1;
ELSE EXECUTE IMMEDIATE c1;
END CASE;

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create or replace procedure proc1
(a1 in varchar2,
 b1 in varchar2,
 c1 in varchar2,
 data_date in varchar2
) is
begin
 if data_date is null then
  dbms_output.put_line('Error parameter: no value for data_date');
 elsif data_date = '01' then
  execute immediate a1;
 elsif data_date = '02' then
  execute immediate b1;
 elsif data_date = '03' then
  execute immediate c1;
 else
  dbms_output.put_line('Error parameter: value for data_date is not in (''01'',''02'',''03'')');
 end if;
end;

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动态拼接好sql 然后判断 执行

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SQL code:
CREATE OR REPLACE PROCEDURE test_proc(v_data_date varchar2)
AS
sql1 VARCHAR2(200);
sql2 VARCHAR2(200);
sql3 VARCHAR2(200);
BEGIN
sql1 := 'SELECT emp, sal, depton from em