DECLARE @StartTime datetime,@EndTime datetime
SELECT @StartTime=GETDATE()
select distinct born_on.name
from born_on,died_on
where (FLOOR(('2012-01-30'-born_on.DOB)/365.25) <= (
select max(FLOOR((died_on.DOD - born_on.DOB)/365.25))
from died_on,born_on
where (died_on.name=born_on.name))
)
and (born_on.name <> All(select name from died_on))
SELECT @EndTime=GETDATE()
SELECT DATEDIFF(ms,@StartTime,@EndTime) AS [Duration in millisecs]
sql:/home/an/Desktop/dbms/query.sql:9: ERROR: Syntax error at or near "@" LINE 1: DECLARE @StartTime datetime,@EndTime datetime
为了测试目的,您也可以使用
原文链接：https://www.f2er.com/postgresql/192589.htmlEXPLAIN ANALYZE.
EXPLAIN ANALYZE
SELECT DISTINCT born_on.name
FROM born_on b
WHERE floor(('2012-01-30'::date - b.dob) / 365.25) <= (
SELECT floor((max(d1.dod - b1.dob)/365.25))
FROM born_on b1
JOIN died_on d1 USING (name)
)
AND NOT EXISTS (
SELECT *
FROM died_on d2
WHERE d2.name = b.name
);
显示查询计划以外的总运行时间.执行几次以排除工件.
A couple of options有更多的细节.
