如何在 MySQL 中仅显示总值中的 200 个字符?
mysqlmysqli database
您可以使用 MySQL 中的 LEFT() 显示 MySQL 中整个值中的某些字符。语法如下:
select left(yourColumnName ,200 ) AS anyAliasName from yourTableName;
首先我们创建一个表:
mysql> create table DemoTable (Paragraph longtext); Query OK, 0 rows affected (0.71 sec)
以下是使用 insert 命令在表中插入记录的查询:
mysql> insert into DemoTable values('Introduction to Java,Introduction to C,Introduction to
C++,Introduction to Spring,Introduction to Hibernate,Introduction to Python,Introduction to
MySQL,Introduction to MongoDB,Introduction to SQL Server,Introduction to
ASP.net,Introduction to JSF');
Query OK, 1 row affected (0.13 sec)
以下是使用 select 命令显示表中记录的查询:
mysql> select *from DemoTable;
这将产生以下输出:
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Paragraph | +--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Introduction to Java,Introduction to C,Introduction to C++,Introduction to Spring,Introduction to Hibernate,Introduction to Python,Introduction to MySQL,Introduction to MongoDB,Introduction to SQL Server,Introduction to ASP.net,Introduction to JSF | +--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)
以下查询仅显示总值中的 200 个字符:
mysql> select left(Paragraph ,200) AS `200Characters` from DemoTable;
这将产生以下输出，仅显示前 200 个字符:
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | 200Characters | +----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Introduction to Java,Introduction to C,Introduction to C++,Introduction to Spring,Introduction to Hibernate,Introduction to Python,Introduction to MySQL,Introduction to MongoDB,Introduction to SQL Ser | +----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)
