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From "Dag H. Wanvik (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4) "order by" is not supported for "insert ... select"
Date Wed, 04 Mar 2009 04:51:56 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12678583#action_12678583
] 

Dag H. Wanvik commented on DERBY-4:
-----------------------------------

Knut, its seems it does, cf. these productions (quote):

<query expression> ::=
 [ <with clause> ] <query expression body>
     [ <order by clause> ] [ <result offset clause> ] [ <fetch first clause>
]

<insert statement> ::=
  INSERT INTO <insertion target> <insert columns and source>

<insert columns and source> ::=
    <from subquery>
  | <from constructor>
  | <from default>

<from subquery> ::=
  [ <left paren> <insert column list> <right paren> ]
      [ <override clause> ]
      <query expression> 

This is just the syntax, however, but I haven't found any provision that would bar it.

> "order by" is not supported for "insert ... select"
> ---------------------------------------------------
>
>                 Key: DERBY-4
>                 URL: https://issues.apache.org/jira/browse/DERBY-4
>             Project: Derby
>          Issue Type: New Feature
>          Components: SQL
>            Reporter: Christian d'Heureuse
>            Priority: Minor
>         Attachments: insertOrderBy.diff, insertOrderBy_v2.diff, insertOrderBy_v3.diff,
samples.ij, samples.ij
>
>
> When filling a table with "insert ... select ...", "order by" cannot be specified.
> There is not method to copy a table sorted into another table (except using export/import).
This would be useful to optimize performance for big tables, or to create identity values
that are ascending (related to another column).
> Example:
> create table temp1 (
>    s varchar(10));
> insert into temp1 values 'x','a','c','b','a';
> create table temp2 (
>    i integer not null
>       generated always as identity
>       primary key,
>    s varchar(10));
> insert into temp2 (s)
>    select s from temp1 order by s;
> --> Error: "order by" is not allowed.
> -- trying to use "group by" instead of "oder by":
> insert into temp2 (s)
>    select s from temp1 group by s;
> select * from temp2;
> --> "group by" did not sort the table.

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