Errors may arise at any time while performing SQL(Structured Query Language) coding stages. These errors fall into two main categories: The two basic types of errors are compilation errors and runtime errors. One has to appreciate the difference between these error types to be able to sort out the most efficient way to handle them.

Compilation Errors

Syntax errors are also known as compilation errors and happen at the time of translating the SQL codes into a format that a database engine can execute. Most of these errors are identified before the code is executed through the validation or compilation process.

Common Causes:

1. Syntax Errors: This is the common reason why the compiler issues out compilation errors most of the time. SQL is very rigid in its syntax and even if you make small mistakes such as missing a semicolon or even using an improper keyword, the program will return an error. For example, if one does not use a semicolon to complete a certain sort of statement, then it will result in a compilation error.

2. Data Type Mismatch: To conduct SQL operations one has to pair the data types in some manner. A compilation error is likely to arise when one attempts to perform operations, on the instances of incompatible types, for example, (+) between a string and a number will likely result in a compilation error.

3. Invalid Identifiers: When you name your tables, columns, or variables with unrecognized or wrong names in an SQL statement it will lead to a compilation error.

4. Incorrect SQL Functions or Keywords: Using improper or incorrect transposition in SQL functions, keywords or clauses such as SELECT, WHERE, or GROUP BY leads to a compilation error.

Runtime Errors

On the other hand, there is another type of error called runtime errors and they are those that appear after the code has been compiled and is being run/executed. Such errors tend to originate from problems that are unpinned until the SQL statement engages with the data in your database.

Common Causes:

1. Division by Zero: Indeed, the use or omit operation is one of the most serious runtime errors that occur in SQL, when a program uses a formula that can be mathematically divided by zero, an undefined operation and the query itself fails to run.

2. Null Value Handling: Runtime errors can occur when the code is run and there’s an error of encountering a NULL value. For example, performing arithmetic operations including comparisons with the NULL values yields errors.

3. Permission Denied: Application logic that tries to access or update tables and data for which it is not authorized can lead to runtime errors in SQL Query.

4. Resource Limitations: In some cases, after filling the database server memory or a query fight against time the code may give a runtime error, particularly during specified complex queries and updates.

Key Differences

1. Detection Time: These errors are found during the code validation stages; they do not allow SQL codes to run or execute. But as the name suggests runtime errors are the errors that occur during the execution of a program or more accurately during runtime.

2. Cause: Compilation errors often stem from the syntax of the code; that is, problems with writing the language. On the other hand, runtime errors are the kind that occur as a result of the interaction of the code with real data or because there are finite resources available.

3. Correction Approach: Logical errors are usually more difficult to correct because they can originate from the user’s reason for using SQL, while compilation errors are much easier to deal with since they are concerned with syntax and coding rules which compilers know very well how to identify. Runtime errors, however, involve debugging or permanently checking the logical structure of the code like testing for nulls, and fine-tuning the queries or permissions among others.

Example Scenario

Imagine writing a simple SQL query that retrieves customer data based on their age:

• SELECT customer_name
• FROM customers
• WHERE age = 'twenty'; -- Compilation error

When running this query, it will trigger a compilation error since the data type of ‘twenty’ is a string while the age field is possibly of type numeric. The SQL compiler will point this out to the mismatch when the query is being processed.

In contrast, a query like this:

• SELECT customer_name
• FROM customers
• WHERE 1/age > 5; -- Runtime error

Would compile successfully but when it is run, it returns an error if it comes across a row in which the age field is 0 which is divided by zero.

How to Avoid SQL Errors

• Code Review: To generate results, SQL codes need to be run, and, based on context or syntactic errors, errors such as may come due to data mismatch usually need to be checked before writing the SQL code.
• Data Validation: Ensure that the information you are using is accurate and that no contamination exists in any form. To eliminate most of the runtime errors you have to check for NULL values and also there should be a check for division by zero.
• Testing: It is recommended that you try SQL queries on some dummy data or a small amount of data so that common runtime problems can be discovered easily.

For more SQL info and tips on how to handle errors, visit articles including one about SQLite in Android.

Conclusion

Runtime errors in SQL and compilation errors that occur are some of the common problems one is likely to meet while coding. These are typically picked at the time of compilation because there are syntax checks involved to alert of wrong compilations than at run time where errors are logically developed and data-related anomalies exist. Knowing the variations and using the methods of incredible debugging allows for creating more effective and error-free SQL code for developers.