云数据库 GaussDB-UPDATE:示例

时间：2025-02-12 15:06:00

云数据库 GaussDB

示例

  
       --创建表student1。gaussdb=# CREATE TABLE student1gaussdb=# (gaussdb=#    stuno     int,gaussdb=#    classno   int gaussdb=# )gaussdb=# DISTRIBUTE BY hash(stuno);--插入数据。gaussdb=# INSERT INTO student1 VALUES(1,1);gaussdb=# INSERT INTO student1 VALUES(2,2);gaussdb=# INSERT INTO student1 VALUES(3,3);--查看数据。gaussdb=# SELECT * FROM student1;--直接更新所有记录的值。gaussdb=# UPDATE student1 SET classno = classno*2;--查看数据。gaussdb=# SELECT * FROM student1;--删除表。gaussdb=# DROP TABLE student1;--WHERE CURRENT OF cursor_name用例gaussdb=# CREATE TABLE t1(c1 int, c2 varchar2); -- 创建表gaussdb=# INSERT INTO t1 VALUES(generate_series(1,1000),'abcd'); -- 插入数据gaussdb=# DECLAREgaussdb-# CURSOR cur1 IS SELECT * FROM t1 WHERE c1 = 1 FOR UPDATE;gaussdb-# va t1%rowtype;gaussdb-# BEGINgaussdb$# OPEN cur1;gaussdb$# FETCH cur1 INTO va;gaussdb$# SET t1 SET c2 = c2 || c2  WHERE CURRENT OF  cur1; -- 使用WHERE CURRENT OF cursor_name更新数据gaussdb$# CLOSE cur1;gaussdb$# COMMIT;gaussdb$# END;gaussdb$# /gaussdb=# SELECT * FROM t1 WHERE c1 = 1; -- 查询数据