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问题：SQLAlchemy按降序排列？
回答 0
回答 1
回答 2
回答 3
您可以.desc()像这样在查询中使用函数
使用SQLAlchemy的desc函数
对于官方文档，请使用链接或检查以下代码段
You can use .desc() function in your query just like this
Use of desc function of SQLAlchemy
For official docs please use the link or check below snippet
回答 4
回答 5

问题：SQLAlchemy按降序排列？

如何descending在如下所示的SQLAlchemy查询中使用ORDER BY ？

此查询有效，但以升序返回：

query = (model.Session.query(model.Entry)
        .join(model.ClassificationItem)
        .join(model.EnumerationValue)
        .filter_by(id=c.row.id)
        .order_by(model.Entry.amount) # This row :)
        )

如果我尝试：

.order_by(desc(model.Entry.amount))

然后我得到：NameError: global name 'desc' is not defined。

点击查看英文原文

How can I use ORDER BY descending in a SQLAlchemy query like the following?

This query works, but returns them in ascending order:

query = (model.Session.query(model.Entry)
        .join(model.ClassificationItem)
        .join(model.EnumerationValue)
        .filter_by(id=c.row.id)
        .order_by(model.Entry.amount) # This row :)
        )

If I try:

.order_by(desc(model.Entry.amount))

then I get: NameError: global name 'desc' is not defined.

回答 0

与FYI一样，您也可以将这些内容指定为列属性。例如，我可能已经做过：

.order_by(model.Entry.amount.desc())

这很方便，因为它避免了import，并且可以在其他地方（例如关系定义等）中使用它。

有关更多信息，您可以参考此

点击查看英文原文

Just as an FYI, you can also specify those things as column attributes. For instance, I might have done:

.order_by(model.Entry.amount.desc())

This is handy since it avoids an import, and you can use it on other places such as in a relation definition, etc.

For more information, you can refer this

回答 1

from sqlalchemy import desc
someselect.order_by(desc(table1.mycol))

来自@ jpmc26的用法

点击查看英文原文 
from sqlalchemy import desc
someselect.order_by(desc(table1.mycol))

Usage from @jpmc26

回答 2

您可能要做的另一件事是：

.order_by("name desc")

这将导致：ORDER BY名称desc。这里的缺点是按顺序使用显式列名。

点击查看英文原文

One other thing you might do is:

.order_by("name desc")

This will result in: ORDER BY name desc. The disadvantage here is the explicit column name used in order by.

回答 3

您可以.desc()像这样在查询中使用函数

query = (model.Session.query(model.Entry)
        .join(model.ClassificationItem)
        .join(model.EnumerationValue)
        .filter_by(id=c.row.id)
        .order_by(model.Entry.amount.desc())
        )

这将按金额降序排列，或者 

query = session.query(
    model.Entry
).join(
    model.ClassificationItem
).join(
    model.EnumerationValue
).filter_by(
    id=c.row.id
).order_by(
    model.Entry.amount.desc()
)
)

使用SQLAlchemy的desc函数

from sqlalchemy import desc
query = session.query(
    model.Entry
).join(
    model.ClassificationItem
).join(
    model.EnumerationValue
).filter_by(
    id=c.row.id
).order_by(
    desc(model.Entry.amount)
)
)

对于官方文档，请使用链接或检查以下代码段

sqlalchemy.sql.expression.desc（column）产生一个降序的ORDER BY子句元素。

例如：

from sqlalchemy import desc

stmt = select([users_table]).order_by(desc(users_table.c.name))

将产生如下SQL：

SELECT id, name FROM user ORDER BY name DESC

desc（）函数是ColumnElement.desc（）方法的独立版本，可用于所有SQL表达式，例如：

stmt = select([users_table]).order_by(users_table.c.name.desc())

参数column –一个ColumnElement（例如标量SQL表达式），用于应用desc（）操作。

也可以看看

asc（）

nullsfirst（）

nullslast（）

Select.order_by（）

点击查看英文原文

You can use .desc() function in your query just like this

query = (model.Session.query(model.Entry)
        .join(model.ClassificationItem)
        .join(model.EnumerationValue)
        .filter_by(id=c.row.id)
        .order_by(model.Entry.amount.desc())
        )

This will order by amount in descending order or 

query = session.query(
    model.Entry
).join(
    model.ClassificationItem
).join(
    model.EnumerationValue
).filter_by(
    id=c.row.id
).order_by(
    model.Entry.amount.desc()
)
)

Use of desc function of SQLAlchemy

from sqlalchemy import desc
query = session.query(
    model.Entry
).join(
    model.ClassificationItem
).join(
    model.EnumerationValue
).filter_by(
    id=c.row.id
).order_by(
    desc(model.Entry.amount)
)
)

For official docs please use the link or check below snippet

sqlalchemy.sql.expression.desc(column) Produce a descending ORDER BY clause element.

e.g.:

from sqlalchemy import desc

stmt = select([users_table]).order_by(desc(users_table.c.name))

will produce SQL as:

SELECT id, name FROM user ORDER BY name DESC

The desc() function is a standalone version of the ColumnElement.desc() method available on all SQL expressions, e.g.:

stmt = select([users_table]).order_by(users_table.c.name.desc())

Parameters column – A ColumnElement (e.g. scalar SQL expression) with which to apply the desc() operation.

See also

asc()

nullsfirst()

nullslast()

Select.order_by()

回答 4

你可以试试： .order_by(ClientTotal.id.desc())

session = Session()
auth_client_name = 'client3' 
result_by_auth_client = session.query(ClientTotal).filter(ClientTotal.client ==
auth_client_name).order_by(ClientTotal.id.desc()).all()

for rbac in result_by_auth_client:
    print(rbac.id) 
session.close()
点击查看英文原文

You can try: .order_by(ClientTotal.id.desc())

session = Session()
auth_client_name = 'client3' 
result_by_auth_client = session.query(ClientTotal).filter(ClientTotal.client ==
auth_client_name).order_by(ClientTotal.id.desc()).all()

for rbac in result_by_auth_client:
    print(rbac.id) 
session.close()

回答 5

@Radu答案的补充，与SQL一样，如果您有许多具有相同属性的表，则可以在参数中添加表名。

.order_by("TableName.name desc")
点击查看英文原文

Complementary at @Radu answer, As in SQL, you can add the table name in the parameter if you have many table with the same attribute.

.order_by("TableName.name desc")
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