Author: admin
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Comparing Strings
Oracle SQL allows for robust string comparison, enabling users to evaluate and manipulate textual data effectively. String comparisons are case-sensitive by default, meaning that ‘Laptop’ and ‘laptop’ would be treated as different values. For example: This query retrieves products that match the exact name “Laptop”. To perform case-insensitive comparisons, users can utilize functions such as…
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IN Operator
The IN operator offers a concise way to specify multiple values within a WHERE clause, streamlining queries that need to check for several potential matches. Instead of using multiple OR conditions, the IN operator allows for a cleaner syntax. For example: sqlCopy codeSELECT * FROM employees WHERE department_id IN (10, 20, 30); In this query,…
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LIKE Operator
The LIKE operator is integral for performing pattern matching within SQL queries, especially useful for searching textual data. It allows users to search for a specified pattern in a column and can be combined with wildcard characters to enhance its functionality. The two primary wildcard characters used with LIKE are: For example, the following query…
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BETWEEN Operator
The BETWEEN operator is a powerful SQL construct used to filter records within a specified range, making it highly useful for queries that require range-based comparisons. This operator is inclusive, meaning that it includes both endpoints of the defined range. For example: sqlCopy codeSELECT * FROM products WHERE price BETWEEN 100 AND 200; In this…
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IS NULL and IS NOT NULL
The IS NULL and IS NOT NULL operators are essential tools for handling NULL values in Oracle SQL. NULLs represent missing or undefined data, and SQL treats them differently than standard values. The IS NULL operator is specifically designed to check for NULL values within a column. For example: This query retrieves all employees whose…
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Basic Comparison Operators
Oracle provides several basic comparison operators that are crucial for constructing SQL queries. These operators allow users to evaluate and filter data based on specific conditions. The key comparison operators include: These operators can be effectively utilized in various clauses of SQL queries to filter results based on user-defined conditions. For example, using the >…
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Definition of Comparison Functions
Oracle comparison functions serve as foundational tools within SQL, enabling users to evaluate and compare data values effectively. These functions return boolean results—TRUE, FALSE, or NULL—based on the evaluation of two expressions. They are vital for filtering datasets, enforcing conditions in queries, and executing logical operations. By using comparison functions, SQL users can formulate complex…
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PARTITION BY Clause
The PARTITION BY clause is a critical component of analytic functions, allowing users to define how to group the rows for calculations. By dividing the result set into partitions, each analytic function operates independently within these subsets. For example: This query ranks employees within each department based on salary, providing insights into intra-department performance. The…
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NTILE() Function
The NTILE(n) function is used to distribute the rows in an ordered partition into a specified number of groups or buckets. This is useful for categorizing data into quantiles, such as quartiles or deciles. For instance, to categorize employees into quartiles based on their salaries, you could write: sqlCopy codeSELECT employee_id, salary, NTILE(4) OVER (ORDER…
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LEAD() and LAG() Functions
The LEAD() and LAG() functions allow users to access data from subsequent or preceding rows within the same result set. This capability is invaluable for comparative analysis and trend evaluation. For example, to compare each employee’s salary to the previous employee’s salary, you might use: In this case, LAG(salary) retrieves the salary of the employee…