oracle select 查询时字符连接符

1，在oracle查询时，用"||"进行字符连接；

如：中间加一个空格，也可以加多个空格；

SQL> select ku_id||' '||ku_lid from wk_t_user;

KU_ID||''||KU_LID
----------------------------------------------------
1 guest
2 superman
11 admin
12 info

2，为方便查看查询结果，拼接字符串；

SQL> select ku_id,'''s id is ',ku_lid from wk_t_user;

     KU_ID '''SIDIS' KU_LID
---------- --------- --------------------
         1 's id is  guest
         2 's id is  superman
        11 's id is  admin

3，SQL> select ku_lid ||' is a '||ku_id from wk_t_user;

KU_LID||'ISA'||KU_ID
------------------------------------------------------------------
guest is a 1
superman is a 2
admin is a 11
info is a 12

4，SQL> select ku_lid||' ''s id is '||ku_id from wk_t_user;

KU_LID||'''SIDIS'||KU_ID
----------------------------------------------------------------------
guest 's id is 1
superman 's id is 2
admin 's id is 11