语句使用Oracle IF条件语句控制逻辑流程（oracleif条件）
的基本技巧
Proper use of Oracle IF condition statement to control logic flow
Oracle IF statement provides a simple and effective way to control flow of logic in coding. We can use this statement to build procedures, functions, packages and triggers. This article will discuss the basic skills to use Oracle IF condition statement properly.
First, we should know the syntax of IF condition statement in Oracle. It looks like this:
IF condition
THEN
statement1
ELSE
statement2
END IF;
The IF THEN statement can check the condition and execute the statement1 when the condition is true. The ELSE statement is optional, and then it can execute statement2 when condition is false.
Second, we also need to know how to concatenate multiple conditions in an IF statement. We can use AND and OR logical operator to concatenate multiple conditions in an IF statement. For example,
IF i50 THEN
statement1
ELSE
statement2
END IF;
Third, we should use boolean variables instead of hard coded values in IF statement. When we ask an Oracle function to return a boolean value, it might need more time to run. To avoid this issue, we can store boolean value in a variable then use the variable in IF statement. For example,
Boolean flag = checkFunction();
IF flag THEN
statement1
END IF;
Fourth, we should avoid using more than one ELSE IF statement in IF condition. If we need to use more than one ELSE IF statement, it is better to use CASE statement instead. Besides, we should avoid using SQL statements directly in IF statement. Instead, we should MySQL functions to handle SQL operations, then use the variables returned from functions in IF statement.
Last but not least, we should use proper indent in our coding. By indenting properly, we can easily recognize the logic of our code.
To summarise, proper use of Oracle IF statements is an important skill for programming in Oracle. IF statements are used to control the flow of our logic in coding. We should understand the syntax, how to concatenate multiple conditions, how to use boolean variables, how to avoid complex ELSE IF statement, and how to use proper indent in coding. With these skills, we can easily build procedures, triggers, functions, packages and many other processes.
