Question

我正在尝试编写一个简单的过程，它将用逗号连接三个字段;但棘手的部分是，如果其中一个值丢失，那么我不想在没有第一个值（第二个字段，第三个字段）时看到前面的逗号 db版本：oracle 11gR2：

    Declare
    v_first_name  varchar2(15);
    v_last_name   varchar2(15);
    v_title       varchar2(15);
    ShowResult    varchar2 (50); 

    Begin

    v_first_name := nvl('john', null) ;
    v_last_name  := nvl('lennon',null);
    v_title      := nvl('singer',null);

    ShowResult := v_first_name ||','|| v_last_name ||','|| v_title

    I am expecting from ShowResult be like this : john,lennon, singer.

    But if any of the value v_first_name or v_last_name or v_title 
    is null then, i like to ShowResult in this way : 
        1st scenario: lennon,singer -- if v_first_name is null
        2nd scenario: john,singer   -- if v_last_name  is null
        3rd scenario: singer        -- if first name and last name r null


    DBMS_OUTPUT.PUT_LINE ('Output is '|| ShowResult);

    End;

Answer 1

你可以尝试类似的东西：

ShowResult := LTRIM(COALESCE(v_first_name,'') || NVL2(v_last_name,',','') || COALESCE(v_last_name,'') || NVL2(v_title,',','') || COALESCE(v_title,''),',')

LTRIM（）将删除前导逗号。

带有DECODE的版本：

ShowResult := LTRIM(COALESCE(v_first_name,'') || DECODE(v_last_name,null,'',',') || COALESCE(v_last_name,'') || DECODE(v_title,null,'',',') || COALESCE(v_title,''),',')

我想在字段之间添加逗号

1 个答案: