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Amazon Redshift
Database Developer Guide (API Version 2012-12-01)

WHERE Clause

The WHERE clause contains conditions that either join tables or apply predicates to columns in tables. Tables can be inner-joined by using appropriate syntax in either the WHERE clause or the FROM clause. Outer join criteria must be specified in the FROM clause.

Syntax

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[ WHERE condition ]

condition

Any search condition with a Boolean result, such as a join condition or a predicate on a table column. The following examples are valid join conditions:

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sales.listid=listing.listid sales.listid<>listing.listid

The following examples are valid conditions on columns in tables:

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catgroup like 'S%' venueseats between 20000 and 50000 eventname in('Jersey Boys','Spamalot') year=2008 length(catdesc)>25 date_part(month, caldate)=6

Conditions can be simple or complex; for complex conditions, you can use parentheses to isolate logical units. In the following example, the join condition is enclosed by parentheses.

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where (category.catid=event.catid) and category.catid in(6,7,8)

Usage Notes

You can't use aliases in the WHERE clause to reference select list expressions.

You can't restrict the results of aggregate functions in the WHERE clause; use the HAVING clause for this purpose.

Columns that are restricted in the WHERE clause must derive from table references in the FROM clause.

Example

The following query uses a combination of different WHERE clause restrictions, including a join condition for the SALES and EVENT tables, a predicate on the EVENTNAME column, and two predicates on the STARTTIME column.

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select eventname, starttime, pricepaid/qtysold as costperticket, qtysold from sales, event where sales.eventid = event.eventid and eventname='Hannah Montana' and date_part(quarter, starttime) in(1,2) and date_part(year, starttime) = 2008 order by 3 desc, 4, 2, 1 limit 10; eventname | starttime | costperticket | qtysold ----------------+---------------------+-------------------+--------- Hannah Montana | 2008-06-07 14:00:00 | 1706.00000000 | 2 Hannah Montana | 2008-05-01 19:00:00 | 1658.00000000 | 2 Hannah Montana | 2008-06-07 14:00:00 | 1479.00000000 | 1 Hannah Montana | 2008-06-07 14:00:00 | 1479.00000000 | 3 Hannah Montana | 2008-06-07 14:00:00 | 1163.00000000 | 1 Hannah Montana | 2008-06-07 14:00:00 | 1163.00000000 | 2 Hannah Montana | 2008-06-07 14:00:00 | 1163.00000000 | 4 Hannah Montana | 2008-05-01 19:00:00 | 497.00000000 | 1 Hannah Montana | 2008-05-01 19:00:00 | 497.00000000 | 2 Hannah Montana | 2008-05-01 19:00:00 | 497.00000000 | 4 (10 rows)