All Qcodo Query method calls require a QQ Condition. QQ Conditions allow you to create a nested/hierarchical set of conditions to describe what essentially becomes your WHERE clause in a SQL query statement.

The following is the list of QQ Condition classes and what parameters they take:

• QQ::All()
• QQ::None()
• QQ::Equal(QQNode, Value)
• QQ::NotEqual(QQNode, Value)
• QQ::GreaterThan(QQNode, Value)
• QQ::LessThan(QQNode, Value)
• QQ::GreaterOrEqual(QQNode, Value)
• QQ::LessOrEqual(QQNode, Value)
• QQ::IsNull(QQNode)
• QQ::IsNotNull(QQNode)
• QQ::In(QQNode, array of string/int/datetime)
• QQ::Like(QQNode, string)

For almost all of the above QQ Conditions, you are comparing a column with some value. The QQ Node parameter represents that column. However, value can be either a static value (like an integer, a string, a datetime, etc.) or it can be another QQ Node.

And finally, there are three special QQ Condition classes which take in any number of additional QQ Condition classes:

• QQ::AndCondition()
• QQ::OrCondition()
• QQ::Not() - "Not" can only take in one QQ Condition class

(conditions can be passed in as parameters and/or as arrays)

Because And/Or/Not conditions can take in any other condition, including other And/Or/Not conditions, you can embed these conditions into other conditions to create what ends up being a logic tree for your entire SQL Where clause. See below for more information on this.