The WHERE command defines the initial Working Set for the following Batch Update commands. The Working Set is the collection of products that the following commands will operate on. Only products matching the expression in the WHERE command will be included in the working set.
WHERE expression [ LIMIT expression ]
Examples:
WHERE ebay.active
The WHERE Command in the example above empties the working set then adds products that have active listings on eBay to the Working Set. This selects only products that are listed on eBay.
WHERE ebay.active && ebay.price > 100 LIMIT 1
The WHERE Command in the example above empties the working set then adds one product that has active listings and is priced over $100 on eBay to the Working Set.