#writing
#sql优化
sql
explain select id, mobile from hd_personal_base where mobile is not null;
-- Seq Scan on hd_personal_base (cost=0.00..43992.19 rows=518971 width=19)
-- Filter: (mobile IS NOT NULL)
explain select id, mobile from hd_personal_base where mobile = '13780631839';
-- Seq Scan on hd_personal_base (cost=0.00..45540.99 rows=4 width=19)
-- Filter: ((mobile)::text = '13780631839'::text)
explain select id, mobile from hd_personal_base where id = 891181;
-- Index Scan using pk_personal_base on hd_personal_base (cost=0.42..8.44 rows=1 width=19)
-- Index Cond: (id = 891181)explain select id, mobile from hd_personal_base where mobile is not null;
-- Seq Scan on hd_personal_base (cost=0.00..43992.19 rows=518971 width=19)
-- Filter: (mobile IS NOT NULL)
explain select id, mobile from hd_personal_base where mobile = '13780631839';
-- Seq Scan on hd_personal_base (cost=0.00..45540.99 rows=4 width=19)
-- Filter: ((mobile)::text = '13780631839'::text)
explain select id, mobile from hd_personal_base where id = 891181;
-- Index Scan using pk_personal_base on hd_personal_base (cost=0.42..8.44 rows=1 width=19)
-- Index Cond: (id = 891181)#writing