在sqlite查询的输出中，如何将相同的列名称用作比较联接'；什么是条款？

我的原始问题

在SQLite中执行以下查询时，出现以下错误：

查询错误：滥用聚合：sum（）无法执行语句

当我将

“Loan”

列的名称更改为类似于

Loan\u amount

的名称时，错误消失了，我的查询工作正常。为什么“贷款”有问题

---

中后期披露

我很确定我找到了出错的原因，是不是因为我在与连接的on子句中的

“Loan”

进行比较

---

如果是这样的话，我怎么还能在查询的输出中使用“Loan”这个词作为我的列名呢？

我想你真正的问题是引用错误。SQL中的单引号用于引用字符串文字，双引号用于引用需要区分大小写或包含奇数字符的列名和表名。SQLite相当宽容奇怪的语法，所以它可能是在猜测

“Loan”

的意思，并且猜测不正确。试试这个：

select
    t.*
    , coalesce(sum(ded0.after_tax_ded_amt), 0) as "Loan"
    , coalesce(sum(ded1.after_tax_ded_amt), 0) as ee_advance_amount
from totals t
  left join totals as ded0
    on t.ee_ssn = ded0.ee_ssn
    and t.deduction_code = 'Loan'
    and ded0.deduction_code = 'Loan'
  left join totals as ded1
    on t.ee_ssn = ded1.ee_ssn
    and t.deduction_code = 'EE Advance'
    and ded1.deduction_code = 'EE Advance'
group by t.ee_ssn;

select
    t.*
    , coalesce(sum(ded0.after_tax_ded_amt), 0) as "Loan"
    , coalesce(sum(ded1.after_tax_ded_amt), 0) as ee_advance_amount
from totals t
  left join totals as ded0
    on t.ee_ssn = ded0.ee_ssn
    and t.deduction_code = 'Loan'
    and ded0.deduction_code = 'Loan'
  left join totals as ded1
    on t.ee_ssn = ded1.ee_ssn
    and t.deduction_code = 'EE Advance'
    and ded1.deduction_code = 'EE Advance'
group by t.ee_ssn;