Developing Apama Applications > Developing Apama Applications in EPL > Working with Streams and Stream Queries > Troubleshooting and stream query coding guidelines > Prefer equi-joins to cross-joins
Prefer equi-joins to cross-joins
In a query using an equi-join, the items from the two input sets are joined based on equality of key values. The identification of matching items is very efficient.
Cross-joins have no expressions so it is more efficient to calculate them than equi-joins. However, cross-joins are less preferable to equi-joins if they produce unwanted items that must subsequently be filtered out.
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