pg 如何生成创建表sql语句？

oracle有dbms_metadata.get_ddl；sqlserver可以直接右键；mysql有show create table

但pg好像没有直接的方法，网上找到了几种自己创建函数的方法，收集一下。

法一：

支持生成包含：字段（支持数组类型字段）、约束、索引（支持唯一索引、全类型索引）在内的建表语句。

CREATE OR REPLACE FUNCTION "public"."findattname"("dbinstancename" varchar, "namespace" varchar, "tablename" varchar, "ctype" varchar)
  RETURNS "pg_catalog"."varchar" AS $BODY$
 
declare
tt oid ;
aname character varying default '';
 
begin
       tt := oid from pg_class where relname= tablename 
    and relnamespace =(select oid from pg_namespace  where nspname=namespace and nspowner=(select datdba from pg_database where datname=dbinstancename) ) ;      
       aname:=  array_to_string(
        array(
               select a.attname  from pg_attribute  a 
                where a.attrelid=tt and  a.attnum   in (        
                select unnest(conkey) from pg_constraint c where contype=ctype 
                and conrelid=tt  and array_to_string(conkey,',') is not null  
            ) 
        ),',')
    ;
    
    return aname;
end 
    
    
    $BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100

法二：

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;

下面是函数的用法：

SELECT generate_create_table_statement('tablename');

删除，DROP语句：

DROP FUNCTION generate_create_table_statement(p_table_name varchar);

法三：pg_dump表结构

pg_dump -t 'aschema.atable' --schema-only database-name

参考

如何在postgreSQL中为现有表生成"create table“sql语句 - 问答 - 腾讯云开发者社区-腾讯云