移除 column record 中除了最后 7 个字符之外的所有内容的 MySQL 查询
我们首先创建一个表 −
mysql> create table DemoTable ( Strength text ); Query OK, 0 rows affected (0.51 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable values('John is a good programmer'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values('Chris is a good player in cricket'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Bob is good in algorithm'); Query OK, 1 row affected (0.42 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable
这将产生以下输出 −
+-----------------------------------+ | Strength | +-----------------------------------+ | John is a good programmer | | Chris is a good player in cricket | | Bob is good in algorithm | +-----------------------------------+ 3 rows in set (0.00 sec)
以下是移除 column record 中除了最后 7 个字符之外的所有内容的查询 −
mysql> update DemoTable set Strength=substr(Strength,-7,7); Query OK, 3 rows affected (0.46 sec) Rows matched: 3 Changed: 3 Warnings: 0
让我们再次检查表记录 −
mysql> select *from DemoTable;
这将产生以下输出 −
+----------+ | Strength | +----------+ | grammer | | cricket | | gorithm | +----------+ 3 rows in set (0.00 sec)
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