SQL nâng cao

You will learn to summarize data by calculating key statistics like totals, averages, and counts, enabling you to extract meaningful insights from raw data.

You will learn to break down summary statistics by categories, enabling you to compare metrics across different groups and discover patterns in your data.

You will learn to analyze data across multiple dimensions at once, enabling you to discover nuanced patterns by breaking down summaries along several categories simultaneously.

You will learn to create new columns by combining and calculating values from existing data, enabling you to derive ratios and other metrics not available in the original dataset.

You will learn to handle multi-step calculations and compute percentages of totals, enabling you to build complex metrics that depend on intermediate results.

You will learn to extract specific rows from your data based on conditions, enabling you to focus your analysis on relevant subsets and handle missing values and text patterns.

You will learn to filter data using multiple criteria at once, enabling you to extract precisely the rows you need by combining conditions with AND and OR logic.

You will learn to simplify complex filtering by breaking conditions into separate columns, and to extract the opposite of a filter result, making your analysis more transparent and verifiable.

You will learn to apply different calculations based on specific conditions, enabling you to standardize values, classify data into categories, and handle varied scenarios within your data.

You will learn to calculate summaries that include only values meeting specific criteria, enabling you to compute nuanced metrics like "average of delayed flights only" within each group.