如何在 oracle 的插入查询中使用转义符号？答案

【问题标题】：How to use Escape symbol in insert query on oracle?如何在 oracle 的插入查询中使用转义符号？
【发布时间】：2018-06-06 08:46:39
【问题描述】：

请考虑这种情况

declare 
  lv_sql varchar(4000);
  lv_sql1 varchar(4000);
begin
  lv_sql1 := 'select case_id from tgt where excluded =''N''';
  lv_sql := 'insert into sample values ('||'''select  count(1) from ( '||lv_sql1||')'')';
  execute immediate (lv_sql);
end;

现在如果我执行这个块，那么它会在 oracle 中引发 Missing COMMA 的错误。

【问题讨论】：

这似乎不是有效的 sql，select count(1) from select case，我希望那里有一个括号
v_sql1')' 应该是v_sql1||')'。但我无法真正理解整体结构。另外我不确定转义与问题有什么关系。

标签： oracle plsql sql-insert

【解决方案1】：

这里有两个问题；第一个是关于VALUES 关键字：

SQL> insert into aTable values (select count(*) from dual);
insert into aTable values (select count(*) from dual)
                           *
ERROR at line 1:
ORA-00936: missing expression


SQL> insert into aTable (select count(*) from dual);

1 row created.

第二个是你缺少括号：

SQL> select count(*) from select 1 from dual;
select count(*) from select 1 from dual
                     *
ERROR at line 1:
ORA-00903: invalid table name


SQL> select count(*) from (select 1 from dual);

  COUNT(*)
----------
         1

例如：

SQL> select * from aTable;

no rows selected

SQL> declare
  2      lv_sql1 varchar2(100);
  3      lv_sql  varchar2(100);
  4  begin
  5      lv_sql1 := 'select 1 from dual';
  6      lv_sql  :='insert into aTable (select count(1) from (' ||lv_sql1 || ') )';
  7      --
  8      execute immediate lv_sql;
  9  end;
 10  /

PL/SQL procedure successfully completed.

SQL> select * from aTable;

         N
----------
         1

SQL>

像你这样的桌子：

SQL> create table tgt(case_id, excluded) as (select 'xxx', 'N' from dual);

Table created.

SQL> create table sample(n number);

Table created.

SQL> declare
  2      lv_sql varchar(4000);
  3      lv_sql1 varchar(4000);
  4  begin
  5      lv_sql1 := 'select case_id from tgt where excluded =''N''';
  6      lv_sql := 'insert into sample (select count(1) from ( '||lv_sql1||'))';
  7      execute immediate (lv_sql);
  8  end;
  9  /

PL/SQL procedure successfully completed.

SQL> select * from sample;

         N
----------
         1

【讨论】：