Question

我有一个具有以下结构的db表：

CREATE table credite(
nr_contract char(30),
data_incheierii date,

rata_dobinzii int,
valoare_credit float,

nr_rate int,
cod_client char(30),

PRIMARY key (nr_contract),
FOREIGN KEY(cod_client) REFERENCES clienti(cod_client)
);

一些示例数据：

insert into credite
Values ('xsdfghu77','2007-04-02',7.8,20000,12,'43e3rtysr');

insert into credite
Values ('xdfgui767','1980-04-11',7.8,100000,12,'43e3rtyhu');

insert into credite
Values ('xcvbhyty7','1999-10-01',7.8,300000,24,'43e3rtyhv');

insert into credite
Values ('xzasdrtgh','2000-04-02',5.0,10000,6,'43e3rtysr');

insert into credite
Values ('xsdfghu77','2007-04-02',7.8,20000,12,'43e3rtysr');

我需要找到最大贷款数量的日期。 （data_incheierii，大多数时间都包含在样本数据中）

我试过了：

SELECT 
MAX(d.incheierii) FROM(Select COUNT(data_incheierii) as incheierii from credite) as d

但我无法返回data_incheierii，因为我遇到语法错误。如何正确编写查询？

Answer 1

基本上，你可以这样做：

select date_created_loan, count(*) as cnt
from credite
group by date_created_loan
order by count(*) desc
fetch first 1 row only;

注意：fetch first 1 row only是获取第一行的ANSI标准语法。有些数据库使用limit;有些人使用select top (1);一些人也使用其他结构。

在SQL Server中，您还可以执行以下操作：

select top (1) date_created_loan, count(*) as cnt
from credite
group by date_created_loan
order by count(*) desc;

如果您想要所有最佳日期，可以使用top (1) with ties。

Answer 2

你应该尝试这个SQL查询。

 SELECT top 1 CAST(MONTH(datecolumn) AS VARCHAR(2)) + '-' + CAST(YEAR(datecolumn) AS VARCHAR(4)) AS MonthYear, 
    count(*) AS mycount
    FROM mytablename
    GROUP BY CAST(MONTH(datecolumn) AS VARCHAR(2)) + '-' + CAST(YEAR(datecolumn) AS VARCHAR(4))
    ORDER BY mycount desc

SQL SERVER选择最大贷款月份

2 个答案: