Errors and causes in PHP that are prone to getting query results from a database (Smarty)

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One: Some undefined errors are reported when viewed in the browser:

1. In the query of this day SQL statement may use you in another HTML, the variable name may be wrong, or the variable may not get the value;

2.SQL statement may be wrong, note the column name and table name;

3. Some queries are query after clicking the button, the action path of form form may be wrong;

4. When viewing PHP and HTML files, no code is unified;

5. See if the PHP file is mapped to HTML code;

Two: blank when viewing in browser

1. When viewing PHP and HTML files, no code is unified;

2. See if there is data in the database that conforms to the conditions of the SQL statement;

3. See if there is an error in the Smarty display () in the PHP file

Three: Error errors

1.config.php the path to the file and whether the database is selected correctly;

Four: Method error

1. The method name is incorrectly written. e.g. Mysql_fetch_array () written in Mysql_fetch_query ();

2. When a mysql_fetch_array () error occurs, the SQL statement usually has an error

Errors and causes in PHP that are prone to getting query results from a database (Smarty)