Unknown column type 'column_type' in column 'column_name' - How to solve MySQL error: Unknown column type in column

Title: How to solve MySQL error: Unknown column type in column, specific code example required

Introduction:
Database plays an important role in the application development process role, and MySQL, as one of the commonly used relational database management systems, is widely used in various Web applications and enterprise-level systems. However, in the process of using MySQL to create tables, you sometimes encounter error messages. One of the common errors is "Unknown column type 'column_type' in column 'column_name'" (unknown column type in column). This article will analyze this problem in detail and provide solutions and specific code examples.

1. Problem description
In MySQL, each column needs to specify a specific column type. When we create a table, if we specify a column type that does not exist in MySQL, the error "Unknown column type 'column_type' in column 'column_name'" will appear. This error prompts us for an unrecognized column type and corresponding column name.

2. Solution
There are two main ways to solve this problem:

1. Modify the column type
2. Check and correct the SQL statement
3. Modify column type:
   First of all, we need to understand the basic column types supported by MySQL, such as integer, character, date, etc. You can get more detailed information by consulting the MySQL official documentation. If we use a column type that does not exist when creating a table, we need to modify the column type to a type supported by MySQL. The specific steps are as follows:

Step 1: View the existing table structure
Use the following command to view the table structure in MySQL:
SHOW CREATE TABLE table_name;

For example, we want to view a table structure named "users":
SHOW CREATE TABLE users;

Step 2: Modify the column type
Find the problem column based on the output of the SHOW CREATE TABLE command CREATE TABLE statement. For example, if we want to modify the column type with the column name "column_name", we can use the ALTER TABLE statement to modify the column type. The specific command is as follows:
ALTER TABLE table_name MODIFY COLUMN column_name new_column_type;

For example, we To modify the column named "column_name" from "column_type" to "new_column_type", we can execute the following command:
ALTER TABLE users MODIFY COLUMN column_name new_column_type;

After the modification is completed, use SHOW again The CREATE TABLE command verifies whether the modification takes effect.

2. Check and correct the SQL statement:
Sometimes, we may mistakenly use a non-existent column type in the SQL statement. Before correcting, we should check and confirm whether the type of each column in the SQL statement matches the basic column type supported by MySQL. The specific steps are as follows:

Step 1: Check the SQL statement
Check the column type in the CREATE TABLE statement or ALTER TABLE statement to ensure that the type of each column is correct.

Step 2: Correct the SQL statement
If it is found that non-existent column types are used in the SQL statement, we need to modify these column types to types supported by MySQL.

Specific example:

CREATE TABLE users (
    id INT,
    name VARCHAR(50),
    age column_type   -- 错误列类型
);

Example after correction:

CREATE TABLE users (
    id INT,
    name VARCHAR(50),
    age INT   -- 修改列类型为整型
);

After the correction is completed, execute the corrected SQL statement again.

3. Summary
When we encounter the error "Unknown column type 'column_type' in column 'column_name'" in MySQL, we need to clarify the problem and then choose the corresponding solution. We can solve this problem by modifying the column type or checking and correcting the SQL statement. We should consult the MySQL official documentation to understand the column types supported by MySQL and match them with the column types we use.

In short, by correctly using MySQL column types and SQL statements, we can avoid the "Unknown column type 'column_type' in column 'column_name'" error and ensure the normal operation of the database.

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