psycopg2 中带有标识符的动态 SQL？

Question

int1 = "first"
int2 = "second"
column1 = ['height', 'test1', 'test2']
column2 = ['height', 'width']

int1_attr = [sql.Identifier(int1,s) for s in column1]
int2_attr = [sql.Identifier(int2,s)for s in column2]

qry_str = sql.SQL("CREATE TABLE IF NOT EXISTS {} as (Select {},{}, st_intersection({},{}) from {},{} )").format(
sql.Identifier('Intersection'),
sql.SQL(', ').join(int1_attr),
sql.SQL(', ').join(int2_attr),
sql.Identifier(int1+".geom"),
sql.Identifier(int2+".geom"),
sql.Identifier(int1),
sql.Identifier(int2)
)
print(qry_str.as_string(con))

>> CREATE TABLE IF NOT EXISTS "Intersection" as (Select "first"."height", "first"."test1", "first"."test2","second"."height", "second"."width", st_intersection("first.geom","second.geom") from "first","second" )

嘿，我需要例如 "first"."height" 作为 select 部分中的 "first.height" 但对于所有属性。该代码是我能做的。我无法从中取得任何进展。有什么办法吗？

最后 sql 应该是这样的；

>> CREATE TABLE IF NOT EXISTS "Intersection" as (Select "first"."height" as "first.height", "first"."test1" as "first.test1", "first"."test2" as "first.test2" ,"second"."height" as "second.height", "second"."width" as "second.with", st_intersection("first.geom","second.geom") from "first","second")

Answer 1

您可以使用 Identifier 创建合格的列名：

NAMED_EXPRESSION = '%s as %s'
QUALIFIED_NAME = '%s.%s'
int1_attr = [
    NAMED_EXPRESSION % (
      sql.Identifier(int1, s),
      sql.Identifier(QUALIFIED_NAME % (int1, s))
    ) for s in column1
]

Answer 2

在 int1_attr 中，您只是用 "table"."column" 标识列。您需要做的是将 int1_attr 构建为 "table"."column" AS "table.column"。这可以使用：

int1_attr = [
    sql.SQL("{} AS {}").format(
        sql.Identifier(int1, s),
        sql.Identifier("{}.{}".format(int1, s))
    ) for s in column1
]
int2_attr = [
    sql.SQL("{} AS {}").format(
        sql.Identifier(int2, s),
        sql.Identifier("{}.{}".format(int2, s))
    ) for s in column2
]

psycopg2 中带有标识符的动态 SQL？

Dynamic SQL with Identifier in psycopg2?

python

postgresql

psycopg2