How to use where and join in codeigniter?

@orpha 

In CodeIgniter, the where and join methods are used to filter and join the database queries respectively. Here's how you can use them:

1. The where method is used to add a WHERE clause to the query. It accepts two parameters: the column name and the value to compare against. You can also pass an optional third parameter for comparison operators like =, !=, >, <, etc. Here's an example:

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$this->db->where('column_name', $value);
$this->db->where('column_name !=', $value); // with comparison operators

You can also use arrays to add multiple WHERE clauses. In such cases, an optional second parameter can be used to negate the WHERE clause. Here's an example:

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$where = array('column1' => $value1, 'column2' => $value2);
$this->db->where($where);

1. The join method is used to join two or more tables in a query. It accepts four parameters: the table name to join, the condition, the join type (left, right, inner, etc.), and an optional fifth parameter (a boolean) to escape the identifiers.

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$this->db->join('table_name', 'condition', 'join_type');
$this->db->join('table_name', 'condition', 'join_type', $escape);

Here's an example of joining two tables:

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$this->db->join('users', 'users.id = posts.user_id', 'left');

Note: It is recommended to use CodeIgniter's Active Record class rather than writing the raw SQL queries for better security and maintainability.

Hope this helps!