[20120705]sqlplus 的column xxx noprint.txt

sqlplus中有時候某列很長，不想顯示，一般使用column xxx format a10,限制輸出的長度。
實際上column 還可以加入引數noprint，使該行不顯示，例子如下：

SQL> help column

 COLUMN

 ------

 Specifies display attributes for a given column, such as:

     - text for the column heading

     - alignment for the column heading

     - format for NUMBER data

     - wrapping of column data

 Also lists the current display attributes for a single column

 or all columns.

 COL[UMN] [{column | expr} [option ...] ]

 where option represents one of the following clauses:

     ALI[AS] alias

     CLE[AR]

     ENTMAP {ON|OFF}

     FOLD_A[FTER]

     FOLD_B[EFORE]

     FOR[MAT] format

     HEA[DING] text

     JUS[TIFY] {L[EFT] | C[ENTER] | R[IGHT]}

     LIKE {expr | alias}

     NEWL[INE]

     NEW_V[ALUE] variable

     NOPRI[NT] | PRI[NT]

     NUL[L] text

     OLD_V[ALUE] variable

     ON|OFF

     WRA[PPED] | WOR[D_WRAPPED] | TRU[NCATED]

SQL> column hiredate clear

SQL> column hiredate noprint

SQL> select * from emp  where empno='7369';

     EMPNO ENAME      JOB              MGR        SAL       COMM     DEPTNO

---------- ---------- --------- ---------- ---------- ---------- ----------

      7369 SMITH      CLERK           7902        800                    20

SQL> column hiredate print

SQL> select * from emp  where empno='7369';

     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO

---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------

      7369 SMITH      CLERK           7902 1980-12-17 00:00:00        800                    20