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full join 空值填充 SELECT coalesce( NULL , 0) as tianchong FROM DUAL SELECT coalesce( '' , '0') as tianchong FROM DUAL SELECT A.M, coalesce(B.N, 'X') AS N 阅读全文
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full join ，left join ，right join，inner join 一、full join full join SELECT A.*, B.* FROM (SELECT 0 AS T1 FROM DUAL UNION SELECT 1 AS T1 FROM DUAL UNION 阅读全文
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SQL语句实现按照分组划分优先级 分组划分优先级 SELECT B.* FROM (SELECT A.color, A.P, row_number() over(partition by P order by color desc) rn FROM (SELECT 'red' AS color, ' 阅读全文
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SQL SERVER 中相关的时间 1、获取当前时间 select getdate() 2、截取需要的值 select datepart(year,getdate()) select datepart(month,getdate()) select datepart(day,getdate()) s 阅读全文