MOVE

功能描述

MOVE在不检索数据的情况下重新定位一个游标。MOVE的作用类似于FETCH命令，但只是重定位游标而不返回行。

语法格式

MOVE [ direction [ FROM | IN ] ] cursor_name;

其中direction子句为可选参数。

NEXT
   | PRIOR
   | FIRST
   | LAST
   | ABSOLUTE count
   | RELATIVE count
   | count
   | ALL
   | FORWARD
   | FORWARD count
   | FORWARD ALL
   | BACKWARD
   | BACKWARD count
   | BACKWARD ALL

参数说明

MOVE命令的参数与FETCH的相同，详细请参见FETCH的参数说明。

成功完成时，MOVE命令将返回一个“MOVE count”的标签，count是一个使用相同参数的FETCH命令会返回的行数（可能为零）。

示例

--创建SCHEMA。
gaussdb=# CREATE SCHEMA tpcds;

--创建表tpcds.reason。
gaussdb=# CREATE TABLE tpcds.reason
(
r_reason_sk         INTEGER      NOT NULL,
r_reason_id         CHAR(16)     NOT NULL,
r_reason_desc       VARCHAR(40)
);

--向表中插入多条记录。
gaussdb=# INSERT INTO tpcds.reason VALUES (1, 'AAAAAAAABAAAAAAA', 'Xxxxxxxxx'),(2, 'AAAAAAAACAAAAAAA', ' Xxxxxxxxx'),(3, 'AAAAAAAADAAAAAAA', ' Xxxxxxxxx'),(4, 'AAAAAAAAEAAAAAAA', 'Not the product that was ordered'),(5, 'AAAAAAAAFAAAAAAA', 'Parts missing'),(6, 'AAAAAAAAGAAAAAAA', 'Does not work with a product that I have'),(7, 'AAAAAAAAHAAAAAAA', 'Gift exchange');

--开始一个事务。
gaussdb=# START TRANSACTION;

--定义一个名为cursor1的游标。
gaussdb=# CURSOR cursor1 FOR SELECT * FROM tpcds.reason;

--忽略游标cursor1的前3行。
gaussdb=# MOVE FORWARD 3 FROM cursor1;

--抓取游标cursor1的前4行。
gaussdb=# FETCH 4 FROM cursor1;
 r_reason_sk |   r_reason_id    |                                            r_reason_desc                                             
-------------+------------------+------------------------------------------------------------------------------------------------------
           4 | AAAAAAAAEAAAAAAA | Not the product that was ordered                                                                     
           5 | AAAAAAAAFAAAAAAA | Parts missing                                                                                       
           6 | AAAAAAAAGAAAAAAA | Does not work with a product that I have                                                            
           7 | AAAAAAAAHAAAAAAA | Gift exchange                                                                                       
(4 rows)

--关闭游标。
gaussdb=# CLOSE cursor1;

--结束一个事务。
gaussdb=# END;

--删除表。
gaussdb=# DROP TABLE tpcds.reason;

--删除SCHEMA。
gaussdb=# DROP SCHEMA tpcds CASCADE;

相关链接

CLOSE，FETCH