查找 postgis 表中的哪些列是几何类型，哪些是属性

Question

我需要在 postgres 表中找到所有包含几何值的列，我试图让它像这样工作。但我不确定它是否会一直有效。

list_geometry_columns = pd.read_sql_query(f"""select column_name from information_schema.columns where table_schema = '{schema_name}' and table_name = '{tbl_name}' and data_type='USER-DEFINED'""",con=engine)['column_name'].tolist()
list_attrib_columns = pd.read_sql_query(f"""select column_name from information_schema.columns where table_schema = '{schema_name}' and table_name = '{tbl_name}' and data_type!='USER-DEFINED'""",con=engine)['column_name'].tolist()

在我当前的实现中，“USER-DEFINED”也可能出现在其他列中。

Answer 1

您可以查询geometry_column 视图（或geography_column）以获取几何图形

SELECT *
FROM geometry_columns
WHERE f_table_schema = 'myschema'
AND f_table_name = 'myTable';

或者，您可以获取每个列类型/格式类型的列表并过滤几何：

SELECT
    pg_attribute.attname AS column_name,
    pg_type.typname AS data_type,
    pg_catalog.format_type(pg_attribute.atttypid, pg_attribute.atttypmod) AS format_type
FROM
    pg_catalog.pg_attribute
JOIN pg_catalog.pg_type
    ON pg_attribute.atttypid = pg_type.oid
INNER JOIN
    pg_catalog.pg_class ON pg_class.oid = pg_attribute.attrelid
INNER JOIN
    pg_catalog.pg_namespace ON pg_namespace.oid = pg_class.relnamespace
WHERE
    pg_attribute.attnum > 0
    AND NOT pg_attribute.attisdropped
    --AND pg_type.typname = 'geometry'
    AND pg_namespace.nspname = 'public'
    AND pg_class.relname = 'my_table'
ORDER BY
    attnum ASC;