View source for SQL Pseudo Columns

=PSEUDO COLUMNS=


==Class==
SQL Applications


==Purpose==
Provide extra information about a SELECT row set


==See Also==
[[SQL INSERT|INSERT]], [[SQL SELECT|SELECT]], [[SQL UPDATE|UPDATE]]


==Description==
A Pseudo Column behaves like a table column, but is not actually stored in the table. You can select from Pseudo Columns, but they cannot be updated.  They provide extra information about a row set.



{| class="wikitable"
!Pseudo Columns||Description
|-
|[[CURRVAL]]||The CURRVAL Pseudo Column will return the current sequence number from the specified table.  Sequence numbers can be used for primary and unique index keys.
|-
|[[NEXTVAL]]||The NEXTVAL Pseudo Column will return the next unique sequence number from the specified table.  Sequence numbers can be used for primary and unique index keys.
|-
|[[ROWID]]||The ROWID Pseudo Column will return a number identifying the row’s physical stored position in the table.  The ROWID Pseudo Column can be used to perform singleton selects, or optimize updates of a known ROWID.
|-
|[[ROWNUM]]||The ROWNUM Pseudo Column will return a number indicating the order in which the rows are selected from the table.
|-
|[[SQLCNT]]||The SQLCNT Pseudo Column will return the number of rows affected by the last SQL statement.  For example, after a SELECT statement, SQLCNT will contain the number of rows selected.
|-
|[[SQLCODE]]||The SQLCODE Pseudo Column will return a number indicating the result of the last SQL statement.
|-
|[[SYNCNUM]]||The SYNCNUM pseudo column will return the unique sequence number assigned to a row from the specified table.
|-
|}

[[Category:Documentation]]
[[Category:SQL]]
[[Category:Pseudo Columns]]