How to Group WHERE Clauses in CodeIgniter?

Grouping WHERE Clauses in CodeIgniter

CodeIgniter provides convenient methods for constructing SQL queries using Active Record. For complex queries, it is sometimes necessary to group WHERE clauses for clarity and accuracy.

Problem:

Consider the following SQL code:

WHERE name != 'Joe' AND (age < 69 OR id > 50)

Directly translating this to CodeIgniter's Active Record syntax, we get:

$this->db->select()
->from('users')
->where('name !=', 'Joe')
->where('age <', 69)
->or_where('id <', $id);

However, this query does not correctly group the subclause with parentheses.

Solution:

To group WHERE clauses using parentheses in CodeIgniter, use the group_start() and group_end() methods, as follows:

$this->db->select()
->from('users')
->where('name !=', 'Joe')
->group_start() // Open parentheses
->where('age <', 69)
->or_where('id <', $id)
->group_end(); // Close parentheses

This query will generate the desired SQL code with the subclause enclosed in parentheses.

Considerations for Complex Queries:

In CodeIgniter 3, the group_start() and group_end() methods are available in the database builder, which is accessed via $this->db. In CodeIgniter 4, they are available in the query builder, which is assigned to a variable such as $builder.

When using multiple OR clauses in a complex query, consider using the groupStart() and groupEnd() methods to ensure the operators evaluate in the correct order. This ensures the query produces the intended results.

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