*/ } else { /* Compute stored generated columns */ /* ... */ /* * If the target is a plain table, check the constraints of * the tuple. */ /* ... */ /* * Also check the tuple against the partition constraint, i
表触发器的创建分类 :(before | after) (INSERT | UPDATE | DELETE) (FOR EACH ROW) (WHEN NEW.? and,or OLD.? ... other boolean express ...)(before | after) (INSERT | UPDATE | DELETE | TRUNCATE) (FOR EACH STATEMENT) (WHEN BOOLEAN express except NEW or OLD or columns) 视图On views...
The following illustrates the syntax of the EXCEPT operator. SELECT select_list FROM A EXCEPT SELECT select_list FROM B; The queries that involve the EXCEPT need to follow these rules: The number of columns and their orders must be the same in the two queries. The data types of the respec...
select*fromstarmerx_user_permissionwhere(user_name,location_id,permission_type)notin(('xxx',315,'internal_in_sign')) 回到顶部 43 表大小 --查询单个表的总大小,包括该表的索引大小selectpg_size_pretty(pg_total_relation_size('tab'))assize;--查询所有表空间大小selectspcname, pg_size_pretty(pg_ta...
PostgreSQL 提供 UNION、INTERSECT 和 EXCEPT 子句用于 SELECT 语句之间的交互。UNION 将第二个 SELECT 语句的结果附加到第一个。 INTERSECT 返回两个 SELECT 语句均有的行。EXCEPT 返回第一个 SELECT 语句有而第二个 SELECT 语句没有的行。我们看一个使用 EXCEPT 的例子,该语句返回客户联系信息除非客户一周内已经...
SELECT * FROM crosstab( 'SELECT date, product, quantity FROM sales ORDER BY 1', 'SELECT DISTINCT product FROM sales ORDER BY 1' ) AS sales_pivot(date date, product1 int, product2 int, product3 int); 在上面的示例中,我们使用了两个查询作为crosstab函数的参数。第一个查询用于获取原始数据,第...
indicates the (approximate) number of distinct non-null* data values in the column. The interpretation is:* 0 unknown or not computed* > 0 actual number of distinct values* < 0 negative of multiplier for number of rows* The special negative case allows us to cope with columns that are* ...
postgres=# explain (selectidfromtest_dm)except(selectidfromtest_dm2); QUERY PLAN---HashSetOpExcept(cost=0.00..383303.38rows=1000000width=4)->Append (cost=0.00..355803.34rows=11000017width=4)->Subquery Scanon"*SELECT* 1" (cost=0.00..32346.00rows=1000000width=4)->Seq Scanontest_dm (cost=...
5432/exampledatabase' engine = create_engine(conn_string) conn = engine.connect() dataid = 1001 result = conn.execute("SELECT * FROM ITEMS") df = DataFrame(result.fetchall()) df.columns = result.keys()...
("\nDeleted rows: " + row_count + "\n"); // Select column names from table sqlQuery = "SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'dbo.tb_test'"; cmd = con.CreateCommand(); cmd.CommandText = sqlQuery; SqlDataReader read...