spool命令

最近工作中，需对数据进行比对。在此之前，则需将数据导出。想到以前用过的spool命令，实验一番，分享如下：

需建SQL执行脚本，内容如下：

set feedback off   --关掉行数显示
set heading off     --关掉标题行
set termout off    --关掉终端显示
set echo off         --关掉回显
set pagesize 0     --去掉头顶的空行
set trims on        --去掉空字符
spool /home/oracle/test.txt
select * from dept;
spool off

执行该脚本，最后/home/oracle/test.txt显示的内容即为表dept的数据：

50 IT CHINA
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 IT CHICAGO
40 OPERATIONS BOSTON

没有开头的SQL> select * from dept;和结尾的SQL> spool off

结合官档，总结一下SQL*Plus关于格式输出的命令：

SET ECHO {ON | OFF}                       Controls whether the START command lists each command in a script as the command is executed.

SET FEED[BACK] {6 | n | ON | OFF}    Displays the number of records returned by a query when a query selects at least n records.

SET HEA[DING] {ON | OFF}                Controls printing of column headings in reports.

SET LIN[ESIZE] {80 | n}                    Sets the total number of characters that SQL*Plus displays on one line before beginning a new line.

SET LONG {80 | n}                            Sets maximum width (in bytes) for displaying LONG, BLOB, BFILE, CLOB, NCLOB and XMLType values; and for                                                      copying LONG values.

SET PAGES[IZE] {14 | n}                   Sets the number of lines in each page. 

SET TERM[OUT] {ON | OFF}               Controls the display of output generated by commands executed from a script.

SET TI[ME] {ON | OFF}                      Controls the display of the current time.

SET TIMI[NG] {ON | OFF}                   Controls the display of timing statistics.

SET TRIMS[POOL] {ON | OFF}             Determines whether SQL*Plus puts trailing blanks at the end of each spooled line.

SET TRIM[OUT] {ON | OFF}                Determines whether SQL*Plus puts trailing blanks at the end of each displayed line.

SET VER[IFY] {ON | OFF}                   Controls whether SQL*Plus lists the text of a SQL statement or PL/SQL command before and after SQL*Plus

                                                      replaces substitution variables with values.

SET WRA[P] {ON | OFF}                     Controls whether SQL*Plus truncates the display of a SELECTed row if it is too long for the current line width

PS：关于SET ECHO语句，从定义上看有点费解，下面我们来看一下实验结果：

一、 SET ECHO OFF

      1> 编辑SQL脚本t1.sql如下：

          set echo off

          select * from dept;

       2> 执行该脚本       

SQL> @t1.sql

    DEPTNO DNAME      LOC
---------- -------------- -------------
    50 IT          CHINA
    10 ACCOUNTING      NEW YORK
    20 RESEARCH      DALLAS
    30 IT          CHICAGO
    40 OPERATIONS      BOSTON

二、 SET ECHO ON

      1> 编辑SQL脚本t1.sql如下：

          set echo on

          select * from dept;

      2> 执行该脚本

SQL> @t1.sql
SQL> select * from dept;

    DEPTNO DNAME      LOC
---------- -------------- -------------
    50 IT          CHINA
    10 ACCOUNTING      NEW YORK
    20 RESEARCH      DALLAS
    30 IT          CHICAGO
    40 OPERATIONS      BOSTON