例如,要查询名为employees的表中的所有字段名称,可以使用以下SQL语句: SELECT column_name FROM information_schema.columns WHERE table_name ='employees'; 我是木头左,感谢各位童鞋的点赞、收藏,我们下期更精彩!
frompg_class cjoinpg_tables donc.relname=d.tablenamewherec.relnamein(selectnamefromtb)andd.schemaname='tp'orderbyc.relnameasc 6、使用视图查询表名及字段 SELECTdistinctTABLE_NAME,COLUMN_NAMEFROMINFORMATION_SCHEMA.COLUMNSWHEREtable_schema='ods'ANDtable_nameNOTSIMILARTO'%_20[0-9]+' 二、会话及锁...
select col.table_schema, col.table_name, col.ordinal_position, col.column_name, col.data_type, col.character_maximum_length, col.numeric_precision, col.numeric_scale, col.is_nullable, col.column_default, des.description from information_schema.columns col left join pg_description des on col.t...
select [level], column, expr... from table [where condition] start with condition connect by [prior column1= column2 | column1 = prior column2]; 1. 2. 3. 4. 5. 2 语法解释 层次查询是通过start with和connect by子句标识的: 1.其中level关键字是可选的,表示等级,1表示root,2表示root的chi...
SELECTcolumn1,column2FROMtable_nameWHEREconditionORDERBYcolumn1ASC|DESC; JOIN 操作 🤝 PostgreSQL 支持多种类型的JOIN操作,包括INNER JOIN,LEFT JOIN,RIGHT JOIN, 和FULL OUTER JOIN。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 SELECTcolumnsFROMtable1INNERJOINtable2ONtable1.column=table2.column; ...
2、相当于mysql的show tables;SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';public 是默认的schema的名字3、相当与mysql的describe table_name;SELECT column_name FROM information_schema.columns WHERE table_name ='table_name';'table_name'是要查询的表的名字...
alter table t_test add column user_code int GENERATED ALWAYS AS(user_id) stored; 创建成功! 添加虚拟列 查看表中这个列是否有数据? select user_code,user_id,idfrom t_test; 查看表数据 首先可以查询这个列,可以看到列user_code和user_id的数据是一致的!
psql -E \dp+ *** QUERY *** SELECT n.nspname as "Schema", c.relname as "Name", CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'm' THEN 'materialized view' WHEN 'S' THEN 'sequence' WHEN 'f' THEN 'foreign table' END as "Type", pg_catalog.array_to_str...
接下来运行CREATE TABLE AS来复制该表: create table t_key_event_file_student_100 as select * from t_key_event_file_student; 创建成功后看看它的DDL语句: 再看一下这张表的数据: 如上图,首先第一张图可以看到拷贝后的表结构,那我们再回头看看原始表的表结构好做对比: ...
where table_name = tablename -- and table_schema=namespace order by ordinal_position ) as string_columns ),' , ') ||',' ; -- 约束 tableScript:= tableScript || array_to_string( array( select concat(' CONSTRAINT ',conname ,c ,u,p,f) from ( ...