Mysql 获取引用表的总数';柱
考虑账户和存款数据库:Mysql 获取引用表的总数';柱,mysql,sql,join,sum,Mysql,Sql,Join,Sum,考虑账户和存款数据库: CREATE TABLE accounts ( id int not null primary key, name varchar(63) ); CREATE TABLE deposits ( id int not null primary key, account int references accounts(id), dollars decimal(15, 2), status enum('pending','com
CREATE TABLE accounts (
id int not null primary key,
name varchar(63)
);
CREATE TABLE deposits (
id int not null primary key,
account int references accounts(id),
dollars decimal(15, 2),
status enum('pending','complete')
);
insert into accounts values
(0, 'us'),
(1, 'europe'),
(2, 'asia');
insert into deposits values
(0, 0, 10, 'pending'),
(1, 0, 20, 'complete'),
(2, 1, 100, 'complete'),
(3, 1, 200, 'pending'),
(4, 1, 300, 'complete'),
(5, 2, 1000, 'pending');
我想获得每家银行全部完整的存款的总数,这是预期结果:
+--------+-----+
| us | 20 |
| europe | 400 |
| asia | 0 |
+--------+-----+
这是我尝试过的SQL,但它没有按预期工作:
SELECT
a.name, SUM(d.dollars)
FROM
accounts a
INNER JOIN
deposits d ON (a.id = d.account AND d.status='complete');
这是它给出的结果:
+--------+-----+
| us | 420 |
+--------+-----+
当前代码的
我做错了什么,我怎样才能得到预期的总数?试试这个
SELECT
a.name, coalesce(SUM(d.dollars),0) as sums
FROM
accounts a
left JOIN
deposits d ON (a.id = d.account AND d.status='complete')
group by a.name
order by sums desc
您应该使用LEFT JOIN,还应该使用groupby
试试这个
SELECT
a.name, coalesce(SUM(d.dollars),0) as sums
FROM
accounts a
left JOIN
deposits d ON (a.id = d.account AND d.status='complete')
group by a.name
order by sums desc
您应该使用LEFT JOIN,还应该使用groupby
您应该使用按a.name
(甚至可能是a.id
)和左外部联接进行分组(如果您想获得非当前值)
编辑:
您应该使用按a.name
(或者甚至可能是a.id
)和左外部联接进行分组(如果您想获得非当前值)
编辑:
请尝试以下查询:
SELECT
a.name, IF(SUM(d.dollars) IS NULL, 0, SUM(d.dollars) )
FROM
accounts a
LEFT JOIN
deposits d ON (a.id = d.account AND d.status='complete')
GROUP BY a.name ORDER BY a.id;
请尝试以下查询:
SELECT
a.name, IF(SUM(d.dollars) IS NULL, 0, SUM(d.dollars) )
FROM
accounts a
LEFT JOIN
deposits d ON (a.id = d.account AND d.status='complete')
GROUP BY a.name ORDER BY a.id;
通过将账户与存款合并,您只需确保与账户关联的存款的金额为美元。如果您还想按帐户名称,甚至帐户Id进行分组,那么您将获得一笔金额/银行。通过将帐户与存款合并,您只需确保为链接到帐户的存款合计美元。如果您还想按帐户名甚至帐户Id分组,那么您将得到一笔金额/银行。您忘记了按银行分组您忘记了按银行分组