如何从all_tables中选择表？

Question

我有以下表名称模板，例如，一对夫妇，名字和数字相同：fmj.backup_semaforo_geo_THENUMBER，例如：

select * from fmj.backup_semaforo_geo_06391442
select * from fmj.backup_semaforo_geo_06398164
...

可以说我需要从每个表中选择一列，该表以’fmj.backup_semaforo_geo_％’过滤器成功执行，我尝试这样做：

    SELECT calle --This column is from the backup_semaforo_geo_# tables
     FROM (SELECT table_name
      FROM all_tables
     WHERE owner = 'FMJ' AND table_name LIKE 'BACKUP_SEMAFORO_GEO_%');

但是我正在获取all_tables表名称数据：

TABLE_NAME
----------
BACKUP_SEMAFORO_GEO_06391442
BACKUP_SEMAFORO_GEO_06398164
...

我如何在不获取all_tables输出的情况下实现这一目标？

谢谢。

Answer 1

大概您当前的查询正在获取ORA-00904: "CALLE": invalid identifier，因为子查询没有名为的列CALLE。不幸的是，您不能在运行时那样为查询提供表名，而必须诉诸于动态SQL。

这样的事情将遍历所有表，并且对于每个表都会CALLE从每个表中获取所有值，然后您就可以遍历这些表。我曾经DBMS_OUTPUT显示过它们，假设您是在SQL * Plus或其他可以处理的事情中html" target="_blank">执行的；但您可能想对他们做其他事情。

set serveroutput on

declare
    -- declare a local collection type we can use for bulk collect; use any table
    -- that has the column, or if there isn't a stable one use the actual data
    -- type, varchar2(30) or whatever is appropriate
    type t_values is table of table.calle%type;
    -- declare an instance of that type
    l_values t_values;
    -- declare a cursor to generate the dynamic SQL; where this is done is a
    -- matter of taste (can use 'open x for select ...', then fetch, etc.)
    -- If you run the query on its own you'll see the individual selects from
    -- all the tables
    cursor c1 is
        select table_name,
            'select calle from ' || owner ||'.'|| table_name as query
        from all_tables
        where owner = 'FMJ'
        and table_name like 'BACKUP_SEMAFORO_GEO%'
        order by table_name;
begin
    -- loop around all the dynamic queries from the cursor
    for r1 in c1 loop
        -- for each one, execute it as dynamic SQL, with a bulk collect into
        -- the collection type created above
        execute immediate r1.query bulk collect into l_values;
        -- loop around all the elements in the collection, and print each one
        for i in 1..l_values.count loop
            dbms_output.put_line(r1.table_name ||': ' || l_values(i));
        end loop;
    end loop;
end;
/