Question

我在WHERE语句中插入子查询时遇到了一些麻烦。我到目前为止的代码是：

    select * from (
    SELECT 'P_' dmnsn  AS partition_name,
    decode(dmnsn,'PROMO','CMBD_PROMO',dmnsn_code) AS high_value,
    dmnsn AS part_pre
    FROM
       (select to_char(to_clob(COLUMN_VALUE)) as dmnsn
    from XMLTABLE(to_clob('"CLSTR","CUSTOMER","CALENDAR","TYPE",
    "PROMO","PRODUCT","PRODUCTION","STORE","WAREHOUSE","SALES","PRICE"')))
    ) 
    where ( select count(*) 'TEST_' || substr( partition_name,3) || '_VIEW' ) > 0

显然它不起作用。（我只是把它放在这里给你一个我想要做的事情的一瞥） XMLTABLE的所有视图实际上都存在，看起来像这样＆＃34; TEST_CLSTR_VIEW＆＃34;。我的目标是从XMLTABLE中选择那些创建非空的视图的值（包含一些记录）

Answer 1

您的查询中有几个问题

1 - 在SQL中使用var的数据库对象作为表或列名称是不允许的。所以你应该使用另一个tecnique构建你的查询，例如：构建dinamically服务器端，查询的字符串避免var

2 - 你错过了sub sublect中的FROM子句。

3 - 'P_'dmnsn AS partition_name，是错误的

select * from (
    SELECT 'P_'   dmnsn  AS partition_name,
    decode(dmnsn,'PROMO','CMBD_PROMO',dmnsn_code) AS high_value,
    dmnsn AS part_pre
    FROM
       (select to_char(to_clob(COLUMN_VALUE)) as dmnsn
    from XMLTABLE(to_clob('"CLSTR","CUSTOMER","CALENDAR","TYPE",
    "PROMO","PRODUCT","PRODUCTION","STORE","WAREHOUSE","SALES","PRICE"')))
    ) 
    where ( select count(*) FROM  YOUR_VIEW ) > 0

WHERE语句中的子查询

1 个答案: