SELECT1AScolumn1,'one'AScolumn2UNIONALLSELECT2,'two'UNIONALLSELECT3,'three'; 再如: SELECT * FROM (VALUES(1, 'one'), (2, 'two'), (3, 'three')) ASt(num,letter); with查询 WITH 提供了一种编写辅助语句以用于更大查询的方法。这些语句,通常被称为公用表表达式或 CTE,可以被认为是定义了只...
[ { UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select ] [ ORDER BY expression [ ASC | DESC | USING operator ] [ NULLS { FIRST | LAST } ] [, ...] ] [ LIMIT { count | ALL } ] [ OFFSET start [ ROW | ROWS ] ] [ FETCH { FIRST | NEXT } [ count ] { ROW | RO...
{ UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select ] [ ORDER BY expression [ ASC | DESC | USING operator ] [ NULLS { FIRST | LAST } ] [, ...] ] [ LIMIT { count | ALL } ] [ OFFSET start [ ROW | ROWS ] ] [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS...
declare r record; begin OLD.id := OLD.id+1; NEW.id := NEW.id+1; select 1 as id into r; raise notice '%, old.id:%. new.id:%', TG_NAME, OLD.id, NEW.id; return r; end; language plpgsql; CREATE FUNCTION postgres=# update t_ret set info=’new’ where id=2 returning *;...
例如,SELECT * FROM events WHERE device_id=1 中的device_id 列。 对于分析工作负载(其中大多数查询需要 1-2 秒),请选择一个支持跨工作器节点并行化查询的列。 例如,经常出现在 GROUP BY 子句中的列,或者一次查询多个值的列。 选择存在于大型表的大多数列中的一个列。 应该分布超过 50 GB 的表。 通过...
也可以使用sql语句:select prosrcfrompg_proc where proname=’func_name’ 回到顶部 29. 通过文件导入 psql *** -f ind_statis3.sql 回到顶部 30.修改自增ID Select nextval('id_seq'); CREATE SEQUENCE topo_id_seq START2000; ALTER TABLE"R_LANEINFO_TOPO"ALTER COLUMN"ID"SET DEFAULT nextval('topo...
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...
-- change distribution column SELECT alter_distributed_table('github_events', distribution_column:='event_id'); -- change shard count of all tables in colocation group SELECT alter_distributed_table('github_events', shard_count:=6, cascade_to_colocated:=true); -- change colocation SELECT alte...
使用日历表交叉连接方法: SELECT s.Shop, p.Product, COALESCE(t1.QuantityInStock, 0) AS QuantityInStock FROM (SELECT DISTINCT Shop FROM table1) s CROSS JOIN (SELE...
Select [col1], [col2] SELECT AVG(col1)=avg1 GETDATE() DATEPART() PostgreSQL vs. MSSQL – Data Types PostgreSQL vs. SQL Server Data Types Comparison Table Data TypePostgreSQLSQL Server 64-bit integer BIGINT BIGINT Fixed length byte string BYTEA BINARY(n) 1, 0 or NULL BOOLEAN...