将空字符串转换为NULL日期

Question

如何将包含多个空格的VARCHAR2转换为DATE NULL

Answer 1

在将字符串传递给TRIM

之前，只需TO_DATE字符串

SQL> declare
  2    l_my_string varchar2(10) := '          ';
  3    l_my_date   date;
  4  begin
  5    l_my_date := to_date( trim( l_my_string ),
  6                          'mm/dd/yyyy' );
  7    if( l_my_date is null )
  8    then
  9      dbms_output.put_line( 'Yup, the date is NULL' );
 10    end if;
 11  end;
 12  /
Yup, the date is NULL

PL/SQL procedure successfully completed.