问题
This is a stupid problem, but I can't seem to get around it. I have a query that's causing trouble in an OCI program, so I want to run it manually in SQL*Plus to check if there is any difference there. This is the query:
select e.label as doc_name,
e.url,
i.item_id,
'multi' as form_type
from cr_items i, cr_extlinks e
where i.parent_id = :comment_id
and e.extlink_id = i.item_id
UNION
select null as doc_name,
utl_raw.cast_to_varchar2(DBMS_LOB.SUBSTR(r.content, 2000, 1)) as url,
r.item_id,
'single' as form_type
from cr_revisions r
where r.revision_id = ( select content_item.get_latest_revision(:comment_id) from dual);
end;
I wanted to bind the comment_id to the value 3052753, so I did the following:
DECLARE
comment_id number := 3052753;
BEGIN
select e.label ,
e.url,
i.item_id,
'multi'
from cr_items i, cr_extlinks e
where i.parent_id = :comment_id
and e.extlink_id = i.item_id
UNION
select null ,
utl_raw.cast_to_varchar2(DBMS_LOB.SUBSTR(r.content, 2000, 1)) as url,
r.item_id,
'single'
from cr_revisions r
where r.revision_id = ( select content_item.get_latest_revision(:comment_id) from dual);
END;
/
which gives this error:
ORA-06550: line 4, column 1:
PLS-00428: an INTO clause is expected in this SELECT statement
Now, I'm already unhappy because I don't want to be radically changing this query, but anyway I forge ahead and come up with this (INTO and UNIONs don't go together so smoothly):
DECLARE
comment_id number := 3052753;
x_label VARCHAR2(50);
x_url VARCHAR2(500);
x_item number;
x_thing VARCHAR2(50);
BEGIN
select label, url, item_id, thing into x_label, x_url, x_item, x_thing from (
select e.label ,
e.url,
i.item_id,
'multi' as thing
from cr_items i, cr_extlinks e
where i.parent_id = :comment_id
and e.extlink_id = i.item_id
UNION
select null ,
utl_raw.cast_to_varchar2(DBMS_LOB.SUBSTR(r.content, 2000, 1)) as url,
r.item_id,
'single' as thing
from cr_revisions r
where r.revision_id = ( select content_item.get_latest_revision(:comment_id) from dual)) ;
END;
/
but now, of course because I'm returning more than 1 row, I get the utterly predictable
ORA-01422: exact fetch returns more than requested number of rows
Now, I can go ahead and start using cursors etc, but my little query is getting more and more distorted from its original self. All I wanted to do was to check if the query ran ok with that value of comment_id. Of course, I can just hardcode the comment_id into the query, and that works fine. But it also works fine in the OCI so I'm to reproduce in SQL*PLus the issue with bind variables that I'm seeing in the OCI code. But why is it such a struggle to do this in SQL*Plus? Have I missed something really obvious?
Database is Oracle 10.2.0.1.0 - 64bit running on Red Hat Enterprise Linux ES release 4 (Nahant Update 8)
回答1:
Similar to @Glenn's approach, but you can declare a bind variable in SQL*Plus and use it in a plain SQL query. First declare it with the var[iable] command:
variable comment_id number;
Then set it with the exec[ute] command, which is essentially an anonymous block:
execute :comment_id := 3052753;
Then run your original query with the :comment_id references, and no BEGIN or END:
select e.label as doc_name,
e.url,
i.item_id,
'multi' as form_type
from cr_items i, cr_extlinks e
where i.parent_id = :comment_id
and e.extlink_id = i.item_id
UNION
select null as doc_name,
utl_raw.cast_to_varchar2(DBMS_LOB.SUBSTR(r.content, 2000, 1)) as url,
r.item_id,
'single' as form_type
from cr_revisions r
where r.revision_id = ( select content_item.get_latest_revision(:comment_id) from dual);
I don't think there's much functional difference between the two approaches beyond personal preference, and both also work in SQL Developer (when run as a script). I find this easier when running SQL copied from a Pro*C file which already uses the : bind form, purely because you don't have to modify the code at all.
Incidentally, you can write:
where r.revision_id = ( select content_item.get_latest_revision(:comment_id) from dual)
without the extra select, as:
where r.revision_id = content_item.get_latest_revision(:comment_id)
回答2:
Rather than creating an anonymous block, you probably want to define an environment variable in sqlplus:
DEFINE comment_id = 3052753
Then refer to &comment_id in your query.
select e.label as doc_name,
e.url,
i.item_id,
'multi' as form_type
from cr_items i, cr_extlinks e
where i.parent_id = &comment_id
and e.extlink_id = i.item_id
UNION
select null as doc_name,
utl_raw.cast_to_varchar2(DBMS_LOB.SUBSTR(r.content, 2000, 1)) as url,
r.item_id,
'single' as form_type
from cr_revisions r
where r.revision_id = ( select content_item.get_latest_revision(&comment_id) from dual);
来源：https://stackoverflow.com/questions/11155855/using-bind-variables-in-sql-plus-with-more-than-one-row-returned