EmmyMiao87 commented on issue #1650: Where clause can't push down into the right table of JOIN clasure URL: https://github.com/apache/incubator-doris/issues/1650#issuecomment-521538908 The where predicate could not be pushed down when the predicate is on the outer join table. For example: `select * from a left join b on a.id=b.id where b.id=1;` In some cases, the predicate could be pushed down. In impala, for example: Query: explain select * from customer_address a left join customer_address b on a.ca_address_sk=b.ca_address_sk where b.ca_address_sk=1 +------------------------------------------------------------------------------------+ | Explain String | +------------------------------------------------------------------------------------+ | Estimated Per-Host Requirements: Memory=0B VCores=2 | | WARNING: The following tables are missing relevant table and/or column statistics. | | tpcds_hive.customer_address | | | | PLAN-ROOT SINK | | | | | 04:EXCHANGE [UNPARTITIONED] | | | | | 02:HASH JOIN [LEFT OUTER JOIN, BROADCAST] | | | hash predicates: a.ca_address_sk = b.ca_address_sk | | | other predicates: b.ca_address_sk = 1 | | | | | |--03:EXCHANGE [BROADCAST] | | | | | | | 01:SCAN HDFS [tpcds_hive.customer_address b] | | | partitions=1/1 files=0 size=0B | | | predicates: b.ca_address_sk = 1 | | | | | 00:SCAN HDFS [tpcds_hive.customer_address a] | | partitions=1/1 files=0 size=0B | +------------------------------------------------------------------------------------+
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