PYHTON SQL查询生成器

提问：我正在寻找python的SQL查询构建器（就像在matlab中一样）。我是初学者，不能自己写一个（至今）。您知道用Python编写的开源查询生成器吗？谢谢亚瑟

 

我使用了python-sql库，对此感到非常满意。https://pypi.org/project/python-sql/

 

当然还有其他的：在SQLObject.org中，有一个请参阅SQLBuilder文档，以编程方式构建SQL。正如其他人所建议的那样，您可能还希望查看ORM系统，例如SQLAlchemy，Django ORM或SQLObject.org本身。

 

使用了python-sql库

项目介绍

python-sql是一个以pythonic方式编写SQL查询的库。

安装：

pip install python-sql
pip install python-sql==1.1.0

导入:

>>> from sql import *
>>> from sql.aggregate import *
>>> from sql.conditionals import *

简单查询:

>>> user = Table('user')
>>> select = user.select()
>>> tuple(select)
('SELECT * FROM "user" AS "a"', ())

>>> select = user.select(user.name)
>>> tuple(select)
('SELECT "a"."name" FROM "user" AS "a"', ())

>>> select = user.select(Count(Literal(1)))
>>> tuple(select)
('SELECT COUNT(%s) FROM "user" AS "a"', (1,))

>>> select = user.select(user.name, distinct=True)
>>> tuple(select)
('SELECT DISTINCT "a"."name" FROM "user" AS "a"', ())

>>> select = user.select(user.id, user.name)
>>> tuple(select)
('SELECT "a"."id", "a"."name" FROM "user" AS "a"', ())

条件查询:

>>> select.where = user.name == 'foo'
>>> tuple(select)
('SELECT "a"."id", "a"."name" FROM "user" AS "a" WHERE ("a"."name" = %s)', ('foo',))

>>> select.where = (user.name == 'foo') & (user.active == True)
>>> tuple(select)
('SELECT "a"."id", "a"."name" FROM "user" AS "a" WHERE (("a"."name" = %s) AND ("a"."active" = %s))', ('foo', True))
>>> select.where = user.name == user.login
>>> tuple(select)
('SELECT "a"."id", "a"."name" FROM "user" AS "a" WHERE ("a"."name" = "a"."login")', ())

链接查询:

>>> join = user.join(Table('user_group'))
>>> join.condition = join.right.user == user.id
>>> select = join.select(user.name, join.right.group)
>>> tuple(select)
('SELECT "a"."name", "b"."group" FROM "user" AS "a" INNER JOIN "user_group" AS "b" ON ("b"."user" = "a"."id")', ())

多链接查询:

>>> join1 = user.join(Table('user'))
>>> join2 = join1.join(Table('user'))
>>> select = join2.select(user.id, join1.right.id, join2.right.id)
>>> tuple(select)
('SELECT "a"."id", "b"."id", "c"."id" FROM "user" AS "a" INNER JOIN "user" AS "b" INNER JOIN "user" AS "c"', ())

分组查询:

>>> invoice = Table('invoice')
>>> select = invoice.select(Sum(invoice.amount), invoice.currency,
...         group_by=invoice.currency)
>>> tuple(select)
('SELECT SUM("a"."amount"), "a"."currency" FROM "invoice" AS "a" GROUP BY "a"."currency"', ())

用输出名称查询:

>>> tuple(user.select(user.name.as_('First Name')))
('SELECT "a"."name" AS "First Name" FROM "user" AS "a"', ())

排序查询:

>>> tuple(user.select(order_by=user.date))
('SELECT * FROM "user" AS "a" ORDER BY "a"."date"', ())
>>> tuple(user.select(order_by=Asc(user.date)))
('SELECT * FROM "user" AS "a" ORDER BY "a"."date" ASC', ())
>>> tuple(user.select(order_by=(user.date.asc, user.id.desc)))
('SELECT * FROM "user" AS "a" ORDER BY "a"."date" ASC, "a"."id" DESC', ())

嵌套子查询:

>>> user_group = Table('user_group')
>>> subselect = user_group.select(user_group.user,
...     where=user_group.active == True)
>>> user = Table('user')
>>> tuple(user.select(user.id, where=user.id.in_(subselect)))
('SELECT "a"."id" FROM "user" AS "a" WHERE ("a"."id" IN (SELECT "b"."user" FROM "user_group" AS "b" WHERE ("b"."active" = %s)))', (True,))
>>> tuple(subselect.select(subselect.user))
('SELECT "a"."user" FROM (SELECT "b"."user" FROM "user_group" AS "b" WHERE ("b"."active" = %s)) AS "a"', (True,))

查询其他数据库的表:

>>> other_table = Table('user', 'myschema')
>>> tuple(other_table.select())
('SELECT * FROM "myschema"."user" AS "a"', ())

插入默认值:

>>> tuple(user.insert())
('INSERT INTO "user" DEFAULT VALUES', ())

插入操作:

>>> tuple(user.insert(columns=[user.name, user.login],
...         values=[['Foo', 'foo']]))
('INSERT INTO "user" ("name", "login") VALUES (%s, %s)', ('Foo', 'foo'))
>>> tuple(user.insert(columns=[user.name, user.login],
...         values=[['Foo', 'foo'], ['Bar', 'bar']]))
('INSERT INTO "user" ("name", "login") VALUES (%s, %s), (%s, %s)', ('Foo', 'foo', 'Bar', 'bar'))

插入查询的结果:

>>> passwd = Table('passwd')
>>> select = passwd.select(passwd.login, passwd.passwd)
>>> tuple(user.insert(values=select))
('INSERT INTO "user" SELECT "a"."login", "a"."passwd" FROM "passwd" AS "a"', ())

更新操作:

>>> tuple(user.update(columns=[user.active], values=[True]))
('UPDATE "user" SET "active" = %s', (True,))
>>> tuple(invoice.update(columns=[invoice.total], values=[invoice.amount + invoice.tax]))
('UPDATE "invoice" SET "total" = ("invoice"."amount" + "invoice"."tax")', ())

带条件更新操作:

>>> tuple(user.update(columns=[user.active], values=[True],
...          where=user.active == False))
('UPDATE "user" SET "active" = %s WHERE ("user"."active" = %s)', (True, False))

使用列表更新操作:

>>> group = Table('user_group')
>>> tuple(user.update(columns=[user.active], values=[group.active],
...         from_=[group], where=user.id == group.user))
('UPDATE "user" AS "b" SET "active" = "a"."active" FROM "user_group" AS "a" WHERE ("b"."id" = "a"."user")', ())

删除操作:

>>> tuple(user.delete())
('DELETE FROM "user"', ())

带条件删除操作:

>>> tuple(user.delete(where=user.name == 'foo'))
('DELETE FROM "user" WHERE ("name" = %s)', ('foo',))

带子查询的删除操作:

>>> tuple(user.delete(
...             where=user.id.in_(user_group.select(user_group.user))))
('DELETE FROM "user" WHERE ("id" IN (SELECT "a"."user" FROM "user_group" AS "a"))', ())

Flavors:

>>> select = user.select()
>>> select.offset = 10
>>> Flavor.set(Flavor())
>>> tuple(select)
('SELECT * FROM "user" AS "a" OFFSET 10', ())
>>> Flavor.set(Flavor(max_limit=18446744073709551615))
>>> tuple(select)
('SELECT * FROM "user" AS "a" LIMIT 18446744073709551615 OFFSET 10', ())
>>> Flavor.set(Flavor(max_limit=-1))
>>> tuple(select)
('SELECT * FROM "user" AS "a" LIMIT -1 OFFSET 10', ())

Limit style:

>>> select = user.select(limit=10, offset=20)
>>> Flavor.set(Flavor(limitstyle='limit'))
>>> tuple(select)
('SELECT * FROM "user" AS "a" LIMIT 10 OFFSET 20', ())
>>> Flavor.set(Flavor(limitstyle='fetch'))
>>> tuple(select)
('SELECT * FROM "user" AS "a" OFFSET (20) ROWS FETCH FIRST (10) ROWS ONLY', ())
>>> Flavor.set(Flavor(limitstyle='rownum'))
>>> tuple(select)
('SELECT "a".* FROM (SELECT "b".*, ROWNUM AS "rnum" FROM (SELECT * FROM "user" AS "c") AS "b" WHERE (ROWNUM <= %s)) AS "a" WHERE ("rnum" > %s)', (30, 20))

qmark style:

>>> Flavor.set(Flavor(paramstyle='qmark'))
>>> select = user.select()
>>> select.where = user.name == 'foo'
>>> tuple(select)
('SELECT * FROM "user" AS "a" WHERE ("a"."name" = ?)', ('foo',))

numeric style:

>>> Flavor.set(Flavor(paramstyle='format'))
>>> select = user.select()
>>> select.where = user.name == 'foo'
>>> format2numeric(*select)
('SELECT * FROM "user" AS "a" WHERE ("a"."name" = :0)', ('foo',))