CODEWITHSUNDEEP
pythonsqlalchemy
AP257
AP257

Reputation: 93793

SQLAlchemy ORDER BY DESCENDING?

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.

Upvotes: 674

Views: 689895

Answers (6)

Anand Tripathi
Anand Tripathi

Reputation: 16136

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()

Upvotes: 58

Radu
Radu

Reputation: 1083

One other thing you might do is:

from sqlalchemy.sql import text
...
.order_by(text("name desc")

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

Upvotes: 101

Rick
Rick

Reputation: 16224

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 SQLAlchemy 1.4 Documentation

Upvotes: 1077

ArtEm
ArtEm

Reputation: 947

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()

Upvotes: 18

Michael
Michael

Reputation: 1203

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")

Upvotes: 2

AP257
AP257

Reputation: 93793

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

Usage from @jpmc26

Upvotes: 461

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