Step By Step SQL ( MySQL ) *Best for Newbies* 100+Practice Q

Learn how to use the select query to fetch data from tables in MySQL, selecting all or specific columns, with case-insensitive keywords and practical examples from employees and orders.

Learn to filter data with the where clause by selecting specific rows and columns. Use equals, not equal to, greater than, and less than for numeric and string criteria.

Learn to filter data with the where clause using and or to apply conditions across multiple columns, including equals, not equals, greater than, less than, and between.

Learn to filter data in MySQL using list and range conditions, including in, not in, between, and not between, with examples on country filters and credit limit ranges.

Learn to fetch unique values from a column using select distinct and inspect a table's structure with describe or dc commands, illustrated on an employees table.

Learn how to use column aliases in MySQL to rename display columns and assemble a full name by concatenating first and last names.

Sort data in MySQL using order by to arrange by one or more columns in ascending or descending order. Apply filtering and sort by fields like last name or country.

Master pattern matching in MySQL using the like operator with percent and underscore to filter data, with examples of starts with, ends with, contains, and basic regular expression concepts.

Explore pattern matching in MySQL using percent and underscore to filter records, including exact five-character names and at least eight-character names, with second character and second last character constraints.

Master subqueries by writing a query inside another query, using the inner query’s result as input for the outer query, with examples like filtering customers by average credit limit.

Learn how to fetch null data using sql queries, including is null and is not null, and distinguish null from zero or blank across real tables like employees and customers.

Explore arithmetic operations on column data by calculating credit limits with addition, subtraction, multiplication, and division. Alias the results as new credit limit and select customer number, name, and limits.

Explore deleting data from tables with delete, truncate, and drop—covering conditional and unconditional deletes, structure-preserving truncate, and table-removing drop.

Explore how group functions like min, max, average, sum, and count operate on multiple rows to produce a single result, using the customers table credit limit as examples.

Explore grouping data in sql using group by with aggregates such as count, max, min, and avg to summarize datasets across countries, offices, and job titles.

Explore how to filter data before grouping using where, then apply having to display only groups where the average credit limit is more than 80000 by country.

Explore fetching data from multiple tables using joins, including cartesian (cross) join, left and right outer joins, full outer join, and self join, with practical employee and offices examples.

See how the cross or Cartesian join merges every row from one table with every row from another. The example uses offices and product lines with 5×3 and 7×7 results.

Master inner join, equi join, and simple join by linking two or more tables on matching office codes to reveal employees with their city and location.

Learn how the left join returns all records from the left table and matching records from the right, with nonmatching right data shown as null, illustrated by employees and offices.

Explore right outer join in MySQL, showing all matching rows and all right-side table rows, even when no left-side match, with examples using employees and offices.

a full outer join combines left and right joins to show all records, including unmatched rows from both tables, using a union of the two results.

Apply a self join, equivalent to inner join, to link a table to itself and fetch employee names with their managers by using aliases and matching employee numbers.

Learn how to create new tables by copying an existing table in MySQL, including full data copies, selective data, and creating empty tables with only the structure.

Define a new table by specifying its structure, including columns, data types, primary key, not null constraints, and defaults, then describe the table to verify its schema.

Master inserting data into MySQL tables, covering full and partial rows, primary key constraints, defaults, and both insert into table values and insert into table (columns) values.

Learn to update data in a table with conditional or unconditional update queries, including changing names and date of joining, while primary key constraints prevent duplicates.

Learn to alter table structure with MySQL: add, drop, rename, and modify columns, position new columns after specific ones, and apply constraints like not null and primary key.

Learn how views act as virtual tables in MySQL, created from select statements, not storing data, and how they enhance security by restricting columns and simplifying complex queries.

Understand how indexes speed up select queries by creating an index on a column like country. Learn the trade-offs, including slower inserts, updates, and deletes.

Learn how to combine results from multiple select statements using union and union all in MySQL, ensuring the same number of columns and understanding when duplicates are removed or preserved.

Apply the not null constraint to enforce non-null values in a column when creating or altering a table, ensuring employee name cannot be null.

Explore check constraint usage to enforce a condition on a column, preventing invalid inserts (e.g., salary over 10000) in a sample employees table.

Explore how the default constraint in MySQL assigns a default value to a column when no value is provided, demonstrated through creating a table and inserting rows.

Master the unique key constraint, applying it to one or more columns with nulls allowed, by creating tables and validating inserts to prevent duplicate entries.

demonstrates the primary key constraint, its requirement for unique and not-null values, and that a table can have only one primary key, including composite keys defined by multiple columns.

Explore foreign key constraints in MySQL by linking child and parent tables, enforcing referential integrity during insertions and deletions with practical examples of employee and bonus tables.

Compare primary key and unique key in MySQL, showing how unique values are enforced, null handling differs, and why one primary key exists while multiple unique keys can exist.