需求：构建简单的测试用例，完成演示Vertica导出数据的功能。
测试用例：导出test业务用户t_jingyu表中的数据。
一、初始化测试环境
二、导出数据
三、验证
一、初始化测试环境
业务用户test下创建t_jingyu测试表，并初始化一些数据. 参考《[Vertica 业务用户指定资源池加载数据](http://www.cnblogs.com/jyzhao/p/4916932.html)》构建初始化测试环境。二、导出数据
2.1 vsql命令说明帮助
``` [dbadmin@vertica1 ~]$ vsql --help This is vsql, the Vertica Analytic Database interactive terminal.Usage:
vsql [OPTIONS]... [DBNAME [USERNAME]]
General options:
-d DBNAME specify database name to connect to (default: "dbadmin")
-c COMMAND run only single command (SQL or internal) and exit
-f FILENAME execute commands from file, then exit
-l list available databases, then exit
-v NAME=VALUE set vsql variable NAME to VALUE
-X do not read startup file (~/.vsqlrc)
--help show this help, then exit
--version output version information, then exit
Input and output options:
-a echo all input from script
-e echo commands sent to server
-E display queries that internal commands generate
-q run quietly (no messages, only query output)
-o FILENAME send query results to file (or |pipe)
-n disable enhanced command line editing (readline)
-s single-step mode (confirm each query)
-S single-line mode (end of line terminates SQL command)
Output format options:
-A unaligned table output mode (-P format=unaligned)
-b beep on command completion
-H HTML table output mode (-P format=html)
-t print rows only (-P tuples_only)
-T TEXT set HTML table tag attributes (width, border) (-P tableattr=)
-x turn on expanded table output (-P expanded)
-P VAR[=ARG] set printing option VAR to ARG (see pset command)
-F STRING set field separator for unaligned output (default: "|") (-P fieldsep=)
-R STRING set record separator (default: newline) (-P recordsep=)
Connection options:
-B SERVER:PORT set connection backup server/port (default: not set)
-C enable connection load balancing (default: not enabled)
-h HOSTNAME database server host or socket directory (default: "local socket")
-p PORT database server port (default: "5433")
-U NAME database user name (default: "dbadmin")
-W prompt for password (should happen automatically)
-w PASSWORD database user's password
-k KRB SERVICE Kerberos service name (default: "vertica")
-K KRB HOST Kerberos host name
For more information, type "?" (for vsql commands)
from within vsql, or consult the vsql section in
the Vertica Analytic Database documentation.
<h2 id="2.2"> 2.2 导出全表数据 </h2>
根据vsql参数说明，确定本次导出表数据的命令：
vsql -Utest -wtestpwd -At -F'|' -c "select * from t_jingyu" -o /tmp/t_jingyu_expdata.dat
最终实现将test用户下t_jingyu的数据导出到文件/tmp/t_jingyu_expdata.dat中。
<h2 id="2.3"> 2.3 导出符合指定条件的表数据 </h2>可以指定where条件，只导出符合条件的数据，例如：
vsql -Utest -wtestpwd -At -F'|' -c "select * from t_jingyu where col1=1" -o /tmp/t_jingyu_expdata_col1.dat
这样就只导出col1=1的t_jingyu表中数据到文件/tmp/t_jingyu_expdata_col1.dat中。
<h1 id="3">三、验证</h1>
查看表数据的导出文件/tmp/t_jingyu_expdata.dat内容：
[dbadmin@vertica1 tmp]$ more /tmp/t_jingyu_expdata.dat
4|martin|2014-06-20 00:00:00
1|jingyu|2014-06-19 00:00:00
5|靖宇|2014-06-19 00:00:00
3|alfred|2014-05-20 00:00:00
2|xiaobei|2014-06-20 00:00:00
查看表数据的导出文件/tmp/t_jingyu_expdata_col1.dat内容：
[dbadmin@vertica1 tmp]$ more /tmp/t_jingyu_expdata_col1.dat
1|jingyu|2014-06-19 00:00:00