The SQLQuery API supports ANSI-99 SQL queries against caches. This API allows SQL joins against collocated entries on the same node as well as non-collocated distributed joins. In replicated mode, SQL joins are easy to execute as all entries are replicated in all cluster nodes, but for partitioned mode, a few nodes may not contain the primary backup, hence distributed joins become complex. Apache Ignite recommends to use affinity keys to store related entries together, so a player and their club must be collocated for faster distributed query processing.

Apache Ignite's @QuerySqlField annotation makes fields accessible for SQL queries. We can even index the fields for a faster query by setting the annotation value: @QuerySqlField(index=true).