如何在 MySQL 中仅显示总值中的 200 个字符？

你可以使用 MySQL 中的 LEFT() 函数在 MySQL 中显示全部值的某些字符。以下是语法

select left(yourColumnName ,200 ) AS anyAliasName from yourTableName;

让我们首先创建一个表

mysql> create table DemoTable (Paragraph longtext);
Query OK, 0 rows affected (0.71 sec)

以下查询使用插入命令在表中插入记录

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)

以下查询使用选择命令从表中显示记录

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的 200 个字符

mysql> select left(Paragraph ,200) AS `200Characters` from DemoTable;

这将产生仅显示前 200 个字符的以下输出

+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 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)

更新于： 30-7-2019

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