SQLAlchemy中的VALUES子句

SQLAlchemy中的VALUES子句

插入中的“ VALUES”是标准SQL，独立的“
VALUES”关键字是Postgresql。PGValues上有一份针对此的快速编译器配方（如果有一天我更改了维基，请在此处复制）：

from sqlalchemy import *from sqlalchemy.ext.compiler import compilesfrom sqlalchemy.sql.expression import FromClausefrom sqlalchemy.sql import table, columnclass values(FromClause):    def __init__(self, *args):        self.list = args    def _populate_column_collection(self):        self._columns.update( [("column%d" % i, column("column%d" % i))         for i in xrange(1, len(self.list[0]) + 1)]        )@compiles(values)def compile_values(element, compiler, asfrom=False, **kw):    v = "VALUES %s" % ", ".join(        "(%s)" % ", ".join(compiler.render_literal_value(elem, None) for elem in tup)        for tup in element.list    )    if asfrom:        v = "(%s)" % v    return vif __name__ == '__main__':    t1 = table('t1', column('a'), column('b'))    t2 = values((1, 0.5), (2, -0.5)).alias('weights')    print select([t1, t2]).select_from(t1.join(t2, t1.c.a==t2.c.column2))