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create table tbl (DATETIME date, ORDERID text, ACTION text, TYPE text, PRICE numeric (10,2)); insert into tbl values ('2018-01-01', 'a34hsbf', 'OPEN', 'LONG', 0.23), ('2018-01-02', 'ghs7fa0', 'OPEN', 'SHORT', 0.45), ('2018-01-03', 'a34hsbf', 'CLOSE', 'LONG', 0.47), ('2018-01-03', 'ghs7fa0', 'CLOSE', 'LONG', 0.48);
4 rows affected
 hidden batch(es)

select case when t1.datetime > t2.datetime then t1.datetime else t2.datetime end as datetime, t1.orderid, t1.type, case when t1.type = 'SHORT' then t1.price - t2.price else t2.price - t1.price end as diff from tbl t1 join tbl t2 on t1.orderid = t2.orderid and t1.type = t2.type and t2.action = 'CLOSE' where t1.action = 'OPEN'
datetime orderid type diff
2018-01-03 a34hsbf LONG 0.24
 hidden batch(es)