清除列定义

我对此功能clear columns感到困惑。有人可以向我解释这一点。

我正在脚本中使用它。

    clear columns
COLUMN temp_in_statement new_value str_in_statement
SELECT DISTINCT 
    LISTAGG('''' || MONTHCOVERED || ''' AS ' || to_char(MONTHCOVERED,'MONDDYYYY'),',')
        WITHIN GROUP (ORDER BY MONTHCOVERED) AS temp_in_statement 
    FROM (SELECT DISTINCT trunc(MONTHCOVERED) as MONTHCOVERED FROM bbsm_aaa where trunc(MONTHCOVERED) between '01-AUG-19' and '31-OCT-19');

是否有特定列需要清除?还是我分配的所有列都被删除了?

ruby19830501 回答:清除列定义

HELP在这里是有原因的:)

SQL> help clear

 CLEAR
 -----

 Resets or erases the current value or setting for the specified option.

 CL[EAR] option ...

 where option represents one of the following clauses:
     BRE[AKS]
     BUFF[ER]
     COL[UMNS]
     COMP[UTES]
     SCR[EEN]
     SQL
     TIMI[NG]


SQL>

这与列的内容无关,而是在SQL * Plus中格式化的方式。看这个例子:

首先,使用col命令设置某些列的设置:

SQL> col empno format 9999
SQL> col ename format a5
SQL> col sal format 999g990d00
SQL>
SQL> select empno,ename,sal from emp where rownum < 4;

EMPNO ENAME         SAL
----- ----- -----------
 7369 SMITH      920,00
 7499 ALLEN    1.600,00
 7521 WARD     1.250,00

现在,清除这些设置并查看区别:

SQL> clear col
columns cleared
SQL> select empno,sal from emp where rownum < 4;

     EMPNO ENAME             SAL
---------- ---------- ----------
      7369 SMITH             920
      7499 ALLEN            1600
      7521 WARD             1250

SQL>

如您所见,这些列中的值不会受到影响-只会显示它们的方式。

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