更新时间:2022-05-13 GMT+08:00
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SQL优化

操作场景

在Hive上执行SQL语句查询时,如果语句中存在“(a&b) or (a&c)”逻辑时,建议将逻辑改为“a & (b or c)”

样例

假设条件a为“p_partkey = l_partkey”,优化前样例如下所示:

select
        sum(l_extendedprice* (1 - l_discount)) as revenue
from
        lineitem,
        part
where   
        (
                p_partkey = l_partkey 
                and p_brand = 'Brand#32'
                and p_container in ('SM CASE', 'SM BOX', 'SM PACK', 'SM PKG')
                and l_quantity >= 7 and l_quantity <= 7 + 10
                and p_size between 1 and 5
                and l_shipmode in ('AIR', 'AIR REG')
                and l_shipinstruct = 'DELIVER IN PERSON'
        )
        or
        (       p_partkey = l_partkey 
                and p_brand = 'Brand#35'
                and p_container in ('MED BAG', 'MED BOX', 'MED PKG', 'MED PACK')
                and l_quantity >= 15 and l_quantity <= 15 + 10
                and p_size between 1 and 10
                and l_shipmode in ('AIR', 'AIR REG')
                and l_shipinstruct = 'DELIVER IN PERSON'
        )
        or
        (       p_partkey = l_partkey 
                and p_brand = 'Brand#24'
                and p_container in ('LG CASE', 'LG BOX', 'LG PACK', 'LG PKG')
                and l_quantity >= 26 and l_quantity <= 26 + 10
                and p_size between 1 and 15
                and l_shipmode in ('AIR', 'AIR REG')
                and l_shipinstruct = 'DELIVER IN PERSON'
        )

优化后样例如下所示:

select
        sum(l_extendedprice* (1 - l_discount)) as revenue
from
        lineitem,
        part
where   p_partkey = l_partkey and
        ((
                p_brand = 'Brand#32'
                and p_container in ('SM CASE', 'SM BOX', 'SM PACK', 'SM PKG')
                and l_quantity >= 7 and l_quantity <= 7 + 10
                and p_size between 1 and 5
                and l_shipmode in ('AIR', 'AIR REG')
                and l_shipinstruct = 'DELIVER IN PERSON'
        )
        or
        (
                p_brand = 'Brand#35'
                and p_container in ('MED BAG', 'MED BOX', 'MED PKG', 'MED PACK')
                and l_quantity >= 15 and l_quantity <= 15 + 10
                and p_size between 1 and 10
                and l_shipmode in ('AIR', 'AIR REG')
                and l_shipinstruct = 'DELIVER IN PERSON'
        )
        or
        (
                p_brand = 'Brand#24'
                and p_container in ('LG CASE', 'LG BOX', 'LG PACK', 'LG PKG')
                and l_quantity >= 26 and l_quantity <= 26 + 10
                and p_size between 1 and 15
                and l_shipmode in ('AIR', 'AIR REG')
                and l_shipinstruct = 'DELIVER IN PERSON'
        ))
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