转 SQL*PLUS中的替换变量(& &&)

今天oracle support提供一个脚本，大致如下：

PROMPT ROUTING_SEQUENCE_ID = &ROUT_SEQ_ID

PROMPT OPERATION_SEQUENCE_ID = &OP_SEQ_ID

PROMPT RESOURCE_SEQ_NUM = &RES_SEQ_NUM

PROMPT RESOURCE_ID = &RES_ID

SELECT 
  SCHEDULE_SEQ_NUM SSN,
  BASIS_TYPE BT,
  UOM_CODE UC,
  PRINCIPAL_FLAG PF
FROM 
  MRP_AP_OPERATION_RESOURCES_V
WHERE 
  ROUTING_SEQUENCE_ID = &ROUT_SEQ_ID  AND
  OPERATION_SEQUENCE_ID = &OP_SEQ_ID  AND
  --RESOURCE_ID = &RES_ID  --AND 
  RESOURCE_SEQ_NUM = &RES_SEQ_NUM;

SELECT 
  SCHEDULE_SEQ_NUM SSN,
  BASIS_TYPE BT,
  UOM_CODE UC,
  PRINCIPAL_FLAG PF
FROM 
  MRP_AP_OPERATION_RESOURCES_V
WHERE 
  --ROUTING_SEQUENCE_ID = &ROUT_SEQ_ID  AND 
  --OPERATION_SEQUENCE_ID = &OP_SEQ_ID  AND 
  RESOURCE_ID = &RES_ID  AND
  RESOURCE_SEQ_NUM = &RES_SEQ_NUM;

SELECT 
  SCHEDULE_SEQ_NUM SSN,
  BASIS_TYPE BT,
  UOM_CODE UC,
  PRINCIPAL_FLAG PF
FROM 
  MRP_AP_OPERATION_RESOURCES_V
WHERE 
  ROUTING_SEQUENCE_ID = &ROUT_SEQ_ID  AND
  OPERATION_SEQUENCE_ID = &OP_SEQ_ID  AND
  RESOURCE_ID = &RES_ID;  
  --AND  RESOURCE_SEQ_NUM = &RES_SEQ_NUM

SELECT 
  SCHEDULE_SEQ_NUM,
  NVL(ALTERNATE_NUMBER  ,
  0) ALT_NUM ,
  RESOURCE_SEQ_NUM
FROM 
  MRP_AP_OPERATION_RESOURCES_V
WHERE 
  ROUTING_SEQUENCE_ID = &ROUT_SEQ_ID  AND
  OPERATION_SEQUENCE_ID = &OP_SEQ_ID  AND
  RESOURCE_ID = &RES_ID;

SELECT 
  SCHEDULE_SEQ_NUM,
  RESOURCE_SEQ_NUM,
  SCHEDULE_FLAG
FROM 
  BOM_OPERATION_RESOURCES
WHERE 
  RESOURCE_ID = (&RES_ID/2)  AND
  OPERATION_SEQUENCE_ID = (&OP_SEQ_ID/2);

SELECT 
  REPLACEMENT_GROUP_NUM,
  SCHEDULE_SEQ_NUM,
  SCHEDULE_FLAG,
  SUBSTITUTE_GROUP_NUM
FROM 
  BOM_SUB_OPERATION_RESOURCES
WHERE 
  RESOURCE_ID = (&RES_ID/2)  AND
  OPERATION_SEQUENCE_ID = (&OP_SEQ_ID/2);

我运行的时候发现输入四个变量后，在紧跟着的每个select中还要再次输入，很麻烦。后来查了一下资料知道了&与&&的区别。在这里做个小记录：

&：引用的变量只存在当前的语句中。举例如下：

SQL> select 1+&var from dual;
Enter value for var: 1
old   1: select 1+&var from dual
new   1: select 1+1 from dual

1+1
----------
         2

SQL> /                    --重复执行需要重新输入变量var的值。
Enter value for var: 2
old   1: select 1+&var from dual
new   1: select 1+2 from dual

1+2
----------
         3

&&：引用的变量存在于当前的sesion。举例如下：

SQL> select 1+&&var from dual;
Enter value for var: 1
old   1: select 1+&&var from dual
new   1: select 1+1 from dual

1+1
----------
         2

SQL> /
old   1: select 1+&&var from dual
new   1: select 1+1 from dual

1+1
----------
         2

SQL> select 100+&var from dual;
old   1: select 100+&var from dual
new   1: select 100+1 from dual

100+1
----------
       101

所以我只要在前面的变量前加一个&就使它的作用范围变成session级的了。如下：

PROMPT ROUTING_SEQUENCE_ID = &&ROUT_SEQ_ID

PROMPT OPERATION_SEQUENCE_ID = &&OP_SEQ_ID

PROMPT RESOURCE_SEQ_NUM = &&RES_SEQ_NUM

PROMPT RESOURCE_ID = &&RES_ID

 

http://blog.chinaunix.net/uid-20274021-id-1969700.html