where condition in sql with newly created field

问题

I have the following query, why cant I get my where clause to work? The value does exist in the table.

 Select B.*, B.[RF attribute1] & "|" & B.[RF attribute2] & "|" & B.[RF attribute3] & "|" & B.[RF attribute4] as new_field 
FROM [Black$] as B 
where new_field = "Stack|over||flow"

error message is No value given for one or more required paramters

Edit, Actual data:

+---------------+---------------+---------------+---------------+
| RF attribute1 | RF attribute2 | RF attribute3 | RF attribute4 |
+---------------+---------------+---------------+---------------+
| BONDZERO      | AUD           |               | MID           |
| BONDZERO      | AUD           |               | MID           |
| SWAPZERO      | AUD           |               | MID           |
| SWAPZERO      | AUD           |               | MID           |

which will create a new field like so:

+-------------------+
|     new_field     |
+-------------------+
| BONDZERO|AUD||MID |
| BONDZERO|AUD||MID |
| SWAPZERO|AUD||MID |
| SWAPZERO|AUD||MID |
+-------------------+

Now i am trying to use the where clause BONDZERO|AUD||MID so it only returns the first 2 rows.

回答1:

Access thinks you are trying to pass new_field as a parameter.

You need to rephrase your WHERE clause verbosely:

Select B.*, B.[RF attribute1] & "|" 
          & B.[RF attribute2] & "|" 
          & B.[RF attribute3] & "|" 
          & B.[RF attribute4] as new_field 
FROM [Black$] as B 
where       B.[RF attribute1] & "|" 
          & B.[RF attribute2] & "|" 
          & B.[RF attribute3] & "|" 
          & B.[RF attribute4] = "Stack|over||flow"

回答2:

Use a subquery:

select b.*
from (Select B.*, B.[RF attribute1] & "|" & B.[RF attribute2] & "|" & B.[RF attribute3] & "|" & B.[RF attribute4] as new_field 
      from [Black$] as B 
     ) as b
where new_field = "Stack|over||flow";

来源：https://stackoverflow.com/questions/50683970/where-condition-in-sql-with-newly-created-field

标签

sql

ms-access