我已经在postgreSQL中创建了一个表。我想查看用于创建表的SQL语句,但无法找出它。

如何通过命令行或SQL语句获得Postgres中现有表的创建表SQL语句?


当前回答

你也可以使用一个免费的数据库管理工具,比如DBeaver,它允许你查看表的DDL,这里有一个例子:

其他回答

(注意-此解决方案不适用于PostgreSQL v12+)


我的解决方案是使用psql和-E选项登录postgres db,如下所示:

psql -E -U username -d database   

在psql中,运行以下命令查看postgres用来生成的sql 描述表语句:

-- List all tables in the schema (my example schema name is public)
\dt public.*
-- Choose a table name from above
-- For create table of one public.tablename
\d+ public.tablename  

基于运行这些描述命令后返回的sql,我能够把它们放在一起 下面是PLPGSQL函数:

CREATE OR REPLACE FUNCTION generate_create_table_statement(p_table_name varchar)
  RETURNS text AS
$BODY$
DECLARE
    v_table_ddl   text;
    column_record record;
BEGIN
    FOR column_record IN 
        SELECT 
            b.nspname as schema_name,
            b.relname as table_name,
            a.attname as column_name,
            pg_catalog.format_type(a.atttypid, a.atttypmod) as column_type,
            CASE WHEN 
                (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                 FROM pg_catalog.pg_attrdef d
                 WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef) IS NOT NULL THEN
                'DEFAULT '|| (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                              FROM pg_catalog.pg_attrdef d
                              WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)
            ELSE
                ''
            END as column_default_value,
            CASE WHEN a.attnotnull = true THEN 
                'NOT NULL'
            ELSE
                'NULL'
            END as column_not_null,
            a.attnum as attnum,
            e.max_attnum as max_attnum
        FROM 
            pg_catalog.pg_attribute a
            INNER JOIN 
             (SELECT c.oid,
                n.nspname,
                c.relname
              FROM pg_catalog.pg_class c
                   LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
              WHERE c.relname ~ ('^('||p_table_name||')$')
                AND pg_catalog.pg_table_is_visible(c.oid)
              ORDER BY 2, 3) b
            ON a.attrelid = b.oid
            INNER JOIN 
             (SELECT 
                  a.attrelid,
                  max(a.attnum) as max_attnum
              FROM pg_catalog.pg_attribute a
              WHERE a.attnum > 0 
                AND NOT a.attisdropped
              GROUP BY a.attrelid) e
            ON a.attrelid=e.attrelid
        WHERE a.attnum > 0 
          AND NOT a.attisdropped
        ORDER BY a.attnum
    LOOP
        IF column_record.attnum = 1 THEN
            v_table_ddl:='CREATE TABLE '||column_record.schema_name||'.'||column_record.table_name||' (';
        ELSE
            v_table_ddl:=v_table_ddl||',';
        END IF;

        IF column_record.attnum <= column_record.max_attnum THEN
            v_table_ddl:=v_table_ddl||chr(10)||
                     '    '||column_record.column_name||' '||column_record.column_type||' '||column_record.column_default_value||' '||column_record.column_not_null;
        END IF;
    END LOOP;

    v_table_ddl:=v_table_ddl||');';
    RETURN v_table_ddl;
END;
$BODY$
  LANGUAGE 'plpgsql' COST 100.0 SECURITY INVOKER;

下面是函数用法:

SELECT generate_create_table_statement('tablename');

下面是drop语句,如果你不想让这个函数永久保存:

DROP FUNCTION generate_create_table_statement(p_table_name varchar);

如果你想找到一个表的create语句而不使用pg_dump,这个查询可能对你有用(改变'tablename'与你的表被称为什么):

SELECT                                          
  'CREATE TABLE ' || relname || E'\n(\n' ||
  array_to_string(
    array_agg(
      '    ' || column_name || ' ' ||  type || ' '|| not_null
    )
    , E',\n'
  ) || E'\n);\n'
from
(
  SELECT 
    c.relname, a.attname AS column_name,
    pg_catalog.format_type(a.atttypid, a.atttypmod) as type,
    case 
      when a.attnotnull
    then 'NOT NULL' 
    else 'NULL' 
    END as not_null 
  FROM pg_class c,
   pg_attribute a,
   pg_type t
   WHERE c.relname = 'tablename'
   AND a.attnum > 0
   AND a.attrelid = c.oid
   AND a.atttypid = t.oid
 ORDER BY a.attnum
) as tabledefinition
group by relname;

当直接从psql调用时,这样做是有用的:

\pset linestyle old-ascii

另外,这个线程中的generate_create_table_statement函数工作得很好。

DataGrip具有与pgAdmin相同的功能。你可以右键点击一个表,你会看到选项自动生成创建表语句。

一个简单的解决方案,在纯SQL。 您可以将其扩展到您想要显示的更多属性。

with c as (
SELECT table_name, ordinal_position, 
 column_name|| ' ' || data_type col
, row_number() over (partition by table_name order by ordinal_position asc) rn
, count(*) over (partition by table_name) cnt
FROM information_schema.columns
WHERE table_name   in ('pg_index', 'pg_tables')
order by table_name, ordinal_position
)
select case when rn = 1 then 'create table ' || table_name || '(' else '' end
 || col 
 || case when rn < cnt then ',' else '); ' end
from c 
order by table_name, rn asc;

输出:

create table pg_index(indexrelid oid,
 indrelid oid,
 indnatts smallint,
 indisunique boolean,
 indisprimary boolean,
 indisexclusion boolean,
 indimmediate boolean,
 indisclustered boolean,
 indisvalid boolean,
 indcheckxmin boolean,
 indisready boolean,
 indislive boolean,
 indisreplident boolean,
 indkey ARRAY,
 indcollation ARRAY,
 indclass ARRAY,
 indoption ARRAY,
 indexprs pg_node_tree,
 indpred pg_node_tree);

 create table pg_tables(schemaname name,
 tablename name,
 tableowner name,
 tablespace name,
 hasindexes boolean,
 hasrules boolean,
 hastriggers boolean,
 rowsecurity boolean);

如果您想一次对多个表执行此操作,则需要多次使用-t开关(我花了一些时间才弄清楚为什么逗号分隔的列表不起作用)。此外,将结果发送到外文件或管道到另一台机器上的postgres服务器也很有用

pg_dump -t table1 -t table2 database_name --schema-only > dump.sql

pg_dump -t table1 -t table2 database_name --schema-only | psql -h server_name database_name