Deleting duplicates
使用window function
row_number
對資料partition
舉例:
isnp=# create table student (id serial, name text, age int);
isnp=# d student;
isnp=# with cte as (select *, round(random()*100) as d from generate_series(1,10000) as r) insert into student (name, age) select `lmy`||r, d from cte;
### genetate duplicate row
isnp=# insert into student (name, age) select name, age from student where 100<id and id<200;
isnp=# with xxx (id, name, age, rn) as (select *, row_number() over(partition by name order by id) rn from student) delete from student where id in (select id from xxx where rn > 1);