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I'd like to show the observation number for each record returned by a PostgreSQL query.
I think in 8.4 windowing functions can perform this capability.
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In PostgreSQL, the ROW_NUMBER() function is used to assign a unique integer to every row that is returned by a query. Syntax: ROW_NUMBER() OVER( [PARTITION BY column_1, column_2, …] [ORDER BY column_3, column_4, …] )
ROWID is an indicator in Oracle of the order of rows on disk for a given table. In PostgreSQL, this is implemented with a page and leaf identifier. The identifier is visible in a query as a pseudo column with the name of “ctid”. You can call this column in a query explicitly by name.
If you want to select data from all the columns of the table, you can use an asterisk ( * ) shorthand instead of specifying all the column names. The select list may also contain expressions or literal values. Second, specify the name of the table from which you want to query data after the FROM keyword.
If you'd like to number each row in a result set, SQL provides the ROW_NUMBER() function. This function is used in a SELECT clause with other columns. After the ROW_NUMBER() clause, we call the OVER() function. If you pass in any arguments to OVER , the numbering of rows will not be sorted according to any column.
select row_number() over (order by <field> nulls last) as rownum, * from foo_tbl order by <field> If order is not necessary, this answer may also be simplified:
select row_number() over(), * -- notice: no fields are needed from foo_tbl SQL Fiddle Proof of Concept
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