如何使用查询获取 PostgreSQL 中表的列名和数据类型列表?
SELECT
column_name,
data_type
FROM
information_schema.columns
WHERE
table_name = 'table_name';
通过上面的查询,您可以得到列及其数据类型
打开
psql
命令行并输入:
\d+ table_name
SELECT
a.attname as "Column",
pg_catalog.format_type(a.atttypid, a.atttypmod) as "Datatype"
FROM
pg_catalog.pg_attribute a
WHERE
a.attnum > 0
AND NOT a.attisdropped
AND a.attrelid = (
SELECT c.oid
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relname ~ '^(hello world)$'
AND pg_catalog.pg_table_is_visible(c.oid)
);
关于它的更多信息:http://www.postgresql.org/docs/9.3/static/catalog-pg-attribute.html
如果您有多个具有相同表名的模式,请不要忘记添加模式名称。
SELECT column_name, data_type
FROM information_schema.columns
WHERE table_name = 'your_table_name' AND table_schema = 'your_schema_name';
或使用 psql:
\d+ your_schema_name.your_table_name
支持在特定模式中查找表的列名和类型的版本,并使用不带任何子查询的 JOINs
SELECT
pg_attribute.attname AS column_name,
pg_catalog.format_type(pg_attribute.atttypid, pg_attribute.atttypmod) AS data_type
FROM
pg_catalog.pg_attribute
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_namespace.nspname = 'my_schema'
AND pg_class.relname = 'my_table'
ORDER BY
attnum ASC;
更新 Pratik 答案以支持更多模式和可空值:
SELECT
"pg_attribute".attname as "Column",
pg_catalog.format_type("pg_attribute".atttypid, "pg_attribute".atttypmod) as "Datatype",
not("pg_attribute".attnotnull) AS "Nullable"
FROM
pg_catalog.pg_attribute "pg_attribute"
WHERE
"pg_attribute".attnum > 0
AND NOT "pg_attribute".attisdropped
AND "pg_attribute".attrelid = (
SELECT "pg_class".oid
FROM pg_catalog.pg_class "pg_class"
LEFT JOIN pg_catalog.pg_namespace "pg_namespace" ON "pg_namespace".oid = "pg_class".relnamespace
WHERE
"pg_namespace".nspname = 'schema'
AND "pg_class".relname = 'table'
);
SELECT column_name,data_type
FROM information_schema.columns
WHERE
table_name = 'your_table_name'
AND table_catalog = 'your_database_name'
AND table_schema = 'your_schema_name';
使这个主题“更完整”。
我需要 SELECT 语句(不是表)中的列名和数据类型。
如果您想在 SELECT 语句而不是实际存在的表上执行此操作,您可以执行以下操作:
DROP TABLE IF EXISTS abc;
CREATE TEMPORARY TABLE abc AS
-- your select statement here!
SELECT
*
FROM foo
-- end your select statement
;
select column_name, data_type
from information_schema.columns
where table_name = 'abc';
DROP IF EXISTS abc;
简短的解释,它为您的选择语句创建了一个(临时)表,您可以通过(以及其他)@a_horse_with_no_name 和@selva 提供的查询“调用”它。
希望这有帮助。
--how to get a list column names and datatypes of a table in PostgreSQL?
SELECT DISTINCT
ROW_NUMBER () OVER (ORDER BY pgc.relname , a.attnum) as rowid ,
pgc.relname as table_name ,
a.attnum as attr,
a.attname as name,
format_type(a.atttypid, a.atttypmod) as typ,
a.attnotnull as notnull,
com.description as comment,
coalesce(i.indisprimary,false) as primary_key,
def.adsrc as default
FROM pg_attribute a
JOIN pg_class pgc ON pgc.oid = a.attrelid
LEFT JOIN pg_index i ON
(pgc.oid = i.indrelid AND i.indkey[0] = a.attnum)
LEFT JOIN pg_description com on
(pgc.oid = com.objoid AND a.attnum = com.objsubid)
LEFT JOIN pg_attrdef def ON
(a.attrelid = def.adrelid AND a.attnum = def.adnum)
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = pgc.relnamespace
WHERE 1=1
AND pgc.relkind IN ('r','')
AND n.nspname <> 'pg_catalog'
AND n.nspname <> 'information_schema'
AND n.nspname !~ '^pg_toast'
AND a.attnum > 0 AND pgc.oid = a.attrelid
AND pg_table_is_visible(pgc.oid)
AND NOT a.attisdropped
ORDER BY rowid
;
无需提及架构,您也可以获得所需的详细信息 试试这个查询->
选择列名,数据类型 来自 information_schema.columns 其中 table_name = 'table_name';
下面将列出提供的模式名称中所有表的所有不同数据类型。
\copy (select distinct data_type, column_name from information_schema.columns where table_name in (SELECT tablename FROM pg_catalog.pg_tables WHERE schemaname != 'pg_catalog' AND schemaname != 'information_schema' and schemaname = '<Your schema name>')) to 'datatypes.csv' delimiter as ',' CSV header
创建一个新函数来获取表信息
CREATE FUNCTION xdesc(in t varchar) RETURNS table(column_name varchar,
data_type varchar) AS $$
SELECT column_name, data_type
FROM information_schema.columns
WHERE table_name = $1
$$ LANGUAGE SQL;
select xdesc('rs_rail_job_index')
我发现@Pratik 的答案很重要,但由于某种原因它对我不起作用。如果可以的话,我已经以更简洁的方式重写了它。它更容易理解,它支持模式并且实际上对我有用(
postgres 15
)。
SELECT
a.attname AS colname,
pg_catalog.format_type(a.atttypid, a.atttypmod) AS coltype
FROM
pg_catalog.pg_attribute AS a
WHERE
a.attnum > 0 AND
NOT a.attisdropped AND
a.attrelid = (
SELECT
c.oid AS relid
FROM
pg_catalog.pg_class AS c
WHERE
c.relname = '<YOUR TABLE NAME GOES HERE>'
AND c.relnamespace = (
SELECT
n.oid
FROM
pg_catalog.pg_namespace AS n
WHERE
n.nspname = '<YOUR SCHEMA NAME GOES HERE>'
)
)
;
P.S. 它还支持复合类型(我其实非常需要)。它会返回这样的字符串:
schemaname.tablename
.