使用sqlalchemy生成： SELECT * ... INTO OUTFILE "file";

发布于 2024-11-09 13:20:23 字数 318 浏览 5 评论 0 原文

我最近开始使用 SQLALCHEMY 查询 my-sql 数据库。我想生成一个使用“INTO OUTFILE ”语法将查询结果导出到测试文件的选择语句。例如：

SELECT *
FROM table
INTO OUTFILE '/tmp/export.txt';

有没有办法使用 SQLALCHEMY 生成“INTO OUTFILE...”子句？

如果没有，我可以对 SQLALCHEMY 类之一进行子类化，以便我可以自己构建该子句吗？

谢谢。

原文

I have recently started using SQLALCHEMY to query a my-sql database. I want to generate a select statement that uses the "INTO OUTFILE <file>" syntax to export query results to a test file. For example:

SELECT *
FROM table
INTO OUTFILE '/tmp/export.txt';

Is there a way to generate the "INTO OUTFILE..." clause using SQLALCHEMY?

If not, can I subclass one of the SQLALCHEMY classes so I can build that clause myself?

Thanks.

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梦与时光遇 2024-11-16 13:20:23

我思考并浏览了 SQLAlchemy 网站上的示例并找到了答案。（也发布到 sql-alchemy 用户食谱）

from sqlalchemy import *
from sqlalchemy.sql.expression import Executable, ClauseElement
from sqlalchemy.ext import compiler

class SelectIntoOutfile(Executable, ClauseElement):
    def __init__(self, select, file):
        self.select = select
        self.file = file


@compiler.compiles(SelectIntoOutfile)
def compile(element, compiler, **kw):
    return "%s INTO OUTFILE '%s'" % (
        compiler.process(element.select), element.file
    )


e = SelectIntoOutfile(select([s.dim_date_table]).where(s.dim_date_table.c.Year==2009), '/tmp/test.txt')
print e
eng.execute(e)

I did some thinking and poking around the examples on the SQLAlchemy site and figured it out. (Also posted to sql-alchemy user reciptes)

from sqlalchemy import *
from sqlalchemy.sql.expression import Executable, ClauseElement
from sqlalchemy.ext import compiler

class SelectIntoOutfile(Executable, ClauseElement):
    def __init__(self, select, file):
        self.select = select
        self.file = file


@compiler.compiles(SelectIntoOutfile)
def compile(element, compiler, **kw):
    return "%s INTO OUTFILE '%s'" % (
        compiler.process(element.select), element.file
    )


e = SelectIntoOutfile(select([s.dim_date_table]).where(s.dim_date_table.c.Year==2009), '/tmp/test.txt')
print e
eng.execute(e)

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