sqlalchemy.sql.elements.ColumnClause

Produce a .ColumnClause object.

The .ColumnClause is a lightweight analogue to the _schema.Column class. The _expression.column function can be invoked with just a name alone, as in:

from sqlalchemy import column

id, name = column("id"), column("name")
stmt = select(id, name).select_from("user")

The above statement would produce SQL like:

SELECT id, name FROM user

Once constructed, _expression.column may be used like any other SQL expression element such as within _expression.select constructs:

from sqlalchemy.sql import column

id, name = column("id"), column("name")
stmt = select(id, name).select_from("user")

The text handled by _expression.column is assumed to be handled like the name of a database column; if the string contains mixed case, special characters, or matches a known reserved word on the target backend, the column expression will render using the quoting behavior determined by the backend. To produce a textual SQL expression that is rendered exactly without any quoting, use _expression.literal_column instead, or pass True as the value of :paramref:`_expression.column.is_literal`. Additionally, full SQL statements are best handled using the _expression.text construct.

_expression.column can be used in a table-like fashion by combining it with the .table function (which is the lightweight analogue to _schema.Table ) to produce a working table construct with minimal boilerplate:

from sqlalchemy import table, column, select

user = table("user",
        column("id"),
        column("name"),
        column("description"),
)

stmt = select(user.c.description).where(user.c.name == 'wendy')

A _expression.column / .table construct like that illustrated above can be created in an ad-hoc fashion and is not associated with any _schema.MetaData, DDL, or events, unlike its _schema.Table counterpart.

Create a shallow copy of this ClauseElement.

This method may be used by a generative API. Its also used as part of the "deep" copy afforded by a traversal that combines the _copy_internals() method.

Undocumented

generate table-qualified label

for a table-bound column this is <tablename>_<columnname>.

used primarily for LABEL_STYLE_TABLENAME_PLUS_COL as well as the .columns collection on a Join object.

Return immediate child .visitors.Traversible elements of this .visitors.Traversible.

This is used for visit traversal.

**kw may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).