Re: Capturing the changes in columns in a table
Clemens Ladisch <clemens-P6GI/[email protected]>
| Newsgroups | gmane.comp.db.sqlite.general |
|---|---|
| Message-ID | <[email protected]> |
David Raymond wrote: > My brain started yelling that that needed a "limit 1" on the subquery so that it would only return 1 row. > > How is that handled by other databases? SQL-92 says: | 6.11 <value expression> | | General Rules | | 2) If a <value expression primary> is a <scalar subquery> and the | result of the <subquery> is empty, then the result of the <value | expression primary> is the null value. | | 7.11 <scalar subquery>, <row subquery>, and <table subquery> | | General Rules | | 1) If the cardinality of a <scalar subquery> or a <row subquery> is | greater than 1, then an exception condition is raised: cardinal- | ity violation. But SQL-92 has no easy way to limit the number of rows, and not even trying to retrieve a second row might be easier to implement, so many databases chose not to check for this error. Regards, Clemens _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users