Oracle using dynamic sql when table name is a parameter

问题

I have a SQL query (a store procedure ) that i want to convert to PLSQL I already conver most of the store procedure but i cant convert the following part :

DECLARE lookupTableRow CURSOR FOR
  SELECT TableName FROM SYS_LookUpTable
  OPEN lookupTableRow
  FETCH NEXT FROM lookupTableRow INTO @tableName
  WHILE @@FETCH_STATUS=0
  BEGIN

  SET @sql='SELECT * FROM '+@tableName
EXECUTE sp_executesql @sql

  IF @counter=0
  BEGIN
  INSERT INTO T_TABLE_MAPPING VALUES('P_MAIN_METADATA', 'Table', @tableName)
  END
  ELSE
  BEGIN
  INSERT INTO T_TABLE_MAPPING 
      VALUES(  'P_MAIN_METADATA', 
               'Table' + CONVERT(NVARCHAR(10),@counter), 
               @tableName)
  END

  SET @counter=@counter+1
  FETCH NEXT FROM lookupTableRow INTO @tableName
  END
  CLOSE lookupTableRow
  DEALLOCATE lookupTableRow

As i understand i can't use ORACLE dynamic sql (execute immediate) when the table name is a parameter.

Furthermore when i execute this dynamic query in my SQL store procedure each SELECT statement return me as a result the relevant table rows , those result are different in each loop .

Please advice for any solution * how can i use dynamic sql with table name as parameter ? * how can i use a "dynamic" cursor, in order to be able to display the dynamic results ?

Thanks for the advice

回答1:

If the only thing you don't know how to do here is using a table name dynamically then this is how you can accomplish that

  1  declare
  2     n number;
  3     table_name varchar2(30) := 'dual';
  4  begin
  5     execute immediate 'select count(*) from ' || table_name into n;
  6     dbms_output.put_line(n);
  7* end;
SQL> /
1

回答2:

If you're simply trying to populate a table that obfuscates table names to something else, why do it sequentially forcing the db to change contexts and slow down?

Create table t_table_mapping as 
(    Select 'P_MAIN_METADATA' "P_MAIN_METADATA", 
      'Table' || to_char(rownum) as "Table", table_name 
     from all_tables)

However this doesn't take into account schema names so what owner. So you need to add a where clause to limit to the specific schema you're wanting to do this for.

来源：https://stackoverflow.com/questions/20839882/oracle-using-dynamic-sql-when-table-name-is-a-parameter

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Oracle

dynamic-sql