DB2-LUW:存储过程中的UNION

Question

我尝试在存储过程中运行以下简单的select语句：

P1: BEGIN

    DECLARE v_uid INTEGER;
    
    SELECT  UID
    INTO    v_id
    FROM    TableA
    UNION 
    SELECT  UID
    FROM    TableB
    ;
    
END P1

它在z/OS数据库上运行良好，但对于LUW数据库，我收到以下错误：

 Create‬‎ ‪stored‬‎ ‪procedure‬‎ ‪returns‬‎ ‪SQLCODE‬‎:‪‬‎ ‪‬‎-‪104‬‎,‪‬‎ ‪SQLSTATE‬‎:‪‬‎ ‪42601‬‎.‪
 TEST‬‎:‪‬‎ ‪25‬‎:‪‬‎ ‪An‬‎ ‪unexpected‬‎ ‪token‬‎ ‪‬‎"‪SELECT UID 
 FROM TABLEB"‬‎ ‪was‬‎ ‪found‬‎ ‪following‬‎ ‪‬‎"FROM TABLEA UNION"‬‎.‪‬‎ 
 Expected‬‎ ‪tokens‬‎ ‪may‬‎ ‪include‬‎:‪‬‎ ‪ ‬‎"‪‪<space>"‬‎.‪‬‎.‪‬‎ 
 ‪SQLCODE‬‎=‪‬‎-‪104‬‎,‪‬‎ ‪SQLSTATE‬‎=‪42601‬‎,‪‬‎ ‪DRIVER‬‎=‪4‬‎.‪24‬‎.‪92

在LUW上不允许使用UNION关键字吗？

Answer 1

您必须将union放在subselect中，如

select uid into v_id from
   (select uid from tablea
    union select uid from tableb);