我想做select <column_name> from <table_name> 其中column_name和table_name应该来自cursor。

Question

我想做选择 column_name 从 table_name 哪儿 column_name.

table_name 应该是来自游标。

查询。

DECLARE
COLUMN_NAME VARCHAR(50); 
TABLE_NAME VARCHAR(100); 
schema_name VARCHAR(100); 
A VARCHAR(100); 
B VARCHAR(100); 

CURSOR col_cursor IS 
  select col.owner as schema_name, 
       col.table_name, 
       col.column_name 
  from sys.all_tab_columns col 
  inner join sys.all_tables t 
    on col.owner = t.owner and 
       col.table_name = t.table_name 
where col.owner = 'PIYUSH1910_BEFORE' 
AND
      DATA_TYPE = 'NUMBER' 
AND
      DATA_PRECISION IS NULL 
AND
      col.TABLE_NAME NOT LIKE '%ER%'; 

BEGIN
 OPEN col_cursor; 

 LOOP
  FETCH col_cursor INTO schema_name,TABLE_NAME,COLUMN_NAME; 
  EXIT WHEN col_cursor%NOTFOUND;
  EXECUTE IMMEDIATE ' SELECT '||COLUMN_NAME ||' INTO A from ' || Table_Name || 'WHERE'||COLUMN_NAME||'- TRUNC('||COLUMN_NAME||',2) > 0'; 

  dbms_output.Put_line(A); 

END LOOP; 
CLOSE col_cursor; 
END

但它却抛出了这个错误

错误报告 - ORA -00933: SQL命令没有正确结束 ORA-06512：在第29行00933. 00000 - "SQL命令未正确结束 *Cause: *错误报告 - ORA-00933：SQL命令未正确结束。

Answer 1

INTO 子句必须放在最后，而使用 EXECUTE IMMEDIATE 如下所示。

EXECUTE IMMEDIATE ' SELECT '||COLUMN_NAME ||' from ' 
        || Table_Name || ' WHERE '||COLUMN_NAME||'- TRUNC('||COLUMN_NAME||',2) > 0' 
        INTO A;

另外，前后的空格 WHERE 在上面的解决方案中加入了关键字。

Answer 2

将EXECUTE IMMEDIATE改为。

EXECUTE IMMEDIATE ' SELECT '|| COLUMN_NAME || ' from ' || Table_Name || 
                  ' WHERE ' || COLUMN_NAME || '- TRUNC('||COLUMN_NAME||',2) > 0'
  INTO A;

这就把 "EXECUTE IMMEDIATE "移到了 INTO 子句到正确的位置（在本例中它是 EXECUTE IMMEDIATE 而不是属于 SELECT)，并略微重新编写代码，使列名与例如 WHERE 关键字