使用聯合聲明在pl中創建視圖時出錯sql

Question

我想用兩個表的部分聯合來創建視圖。

下面是聲明：

create view "test" AS 
select 
ppt.reportingtime reportingtime, 
ppt.currency currency, 
ppt.channelid channelid, 
ppt.transactiontype ttype 
FROM preprocessortransactions ppt 
union 
select 
bm.balancetype balancetype 
from balancemovements bm 

該錯誤消息我得到的是以下幾點：

Error starting at line 1 in command:

create view "test" AS SELECT
ppt.reportingtime reportingtime, ppt.currency currency, ppt.channelid channelid, ppt.transactiontype ttype FROM preprocessortransactions ppt union select bm.balancetype balancetype from balancemovements bm

Error at Command Line:1 Column:22 Error report: SQL Error: ORA-01789: query block has incorrect number of result columns 01789. 00000 - "query block has incorrect number of result columns" *Cause:
*Action:

我非常新的PL SQL和我想不通的意義報錯。

我還嘗試在第一個AS運算符之前列出括號中的列名，但沒有成功。

Answer 1

按照使用NULL的要求插入空白。

CREATE VIEW "test" AS 
SELECT ppt.reportingtime reportingtime, ppt.currency currency, ppt.channelid channelid, ppt.transactiontype ttype 
FROM preprocessortransactions ppt 
UNION 
SELECT NULL, NULL, NULL, bm.balancetype balancetype 
FROM balancemovements bm 

Answer 2

在這種情況下工會 & unionall你應該給同桌的屬性在這兩個查詢。

例如：

select a,b,c from test 
union 
--- in this you don't have a,b attribute in your second query, you can use null in their place. 
select '','',c from test 

注意：您可以使用'' or NULL所以您的查詢如：

create view "test" 
as 
    select 
     ppt.reportingtime reportingtime, 
     ppt.currency currency, 
     ppt.channelid channelid, 
     ppt.transactiontype ttype,'' 
    from 
     preprocessortransactions ppt 

    union 

    select 
     '', '', '', '', bm.balancetype balancetype 
    from 
     balancemovements bm 

希望它會幫助你。所有最好的