Definition: Retrieves unique values from a column.
Example:SELECT DISTINCT column1 FROM table;
COUNT() Function:
Definition: Counts the number of rows in a result set.
Example:SELECT COUNT(column1) FROM table WHERE condition;
GROUP BY Clause:
Definition: Groups rows based on the values in specified columns.
Example:SELECT column1, COUNT(column2) FROM table GROUP BY column1;
SELECT Statement:
Retrieves data from one or more tables.
WHERE Clause:
Filters records based on a specified condition.
ORDER BY Clause:
Sorts the result set in ascending or descending order.
GROUP BY Clause:
Groups rows based on the values in specified columns.
COUNT() Function:
Counts the number of rows in a result set.
SUM() Function:
Calculates the sum of values in a numeric column.
AVG() Function:
Calculates the average value of a numeric column.
MIN() Function:
Retrieves the smallest value in a column.
MAX() Function:
Retrieves the largest value in a column.
INNER JOIN:
Combines rows from two or more tables based on a related column.
LEFT JOIN:
Retrieves all rows from the left table and the matched rows from the right table.
RIGHT JOIN:
Retrieves all rows from the right table and the matched rows from the left table.
FULL OUTER JOIN:
Retrieves all rows when there is a match in either the left or right table.
HAVING Clause:
Filters the result set based on aggregate values.
DISTINCT Keyword:
Retrieves unique values from a column.
LIKE Operator:
Searches for a specified pattern in a column.
IN Operator:
Specifies multiple values for a WHERE clause.
BETWEEN Operator:
Retrieves values within a specified range.
CASE Statement:
Performs conditional logic within a query.
UNION Operator:
Combines the result sets of two or more SELECT statements.
DISTINCT Keyword:
Retrieves unique values from a column.
LIKE Operator:
Searches for a specified pattern in a column.
IN Operator:
Specifies multiple values for a WHERE clause.
BETWEEN Operator:
Retrieves values within a specified range.
CASE Statement:
Performs conditional logic within a query.
UNION Operator:
Combines the result sets of two or more SELECT statements.
INTERSECT Operator:
Retrieves common rows between two SELECT statements.
EXCEPT Operator:
Retrieves rows from the first SELECT statement that are not present in the second.
AS Keyword:
Renames a column or table in the result set.
IS NULL Operator:
Checks for NULL values in a column.
IS NOT NULL Operator:
Checks for non-NULL values in a column.
INNER JOIN with USING:
Joins tables based on a common column using the USING keyword.
LEFT JOIN with USING:
Retrieves all rows from the left table and matched rows from the right using the USING keyword.
RIGHT JOIN with USING:
Retrieves all rows from the right table and matched rows from the left using the USING keyword.
FULL OUTER JOIN with USING:
Retrieves all rows when there is a match in either the left or right table using the USING keyword.
COUNT(DISTINCT Column):
Counts the number of unique values in a column.
CONCAT() Function:
Concatenates two or more strings.
UPPER() Function:
Converts a string to uppercase.
LOWER() Function:
Converts a string to lowercase.
LENGTH() Function:
Returns the length of a string.
TRIM() Function:
Removes leading and trailing spaces from a string.
ROUND() Function:
Rounds a numeric value to the nearest integer.
RAND() Function:
Generates a random decimal value between 0 and 1.
CURRENT_DATE Function:
Retrieves the current date.
CURRENT_TIME Function:
Retrieves the current time.
CURRENT_TIMESTAMP Function:
Retrieves the current timestamp.
DATEDIFF() Function:
Calculates the difference between two dates.
COALESCE() Function:
Returns the first non-NULL value in a list.
NULLIF() Function:
Returns NULL if two expressions are equal; otherwise, returns the first expression.
ROW_NUMBER() Function:
Assigns a unique number to each row within a partition of a result set.
RANK() Function:
Assigns a rank to each row within a result set.
DENSE_RANK() Function:
Assigns a dense rank to each row within a result set.
LEAD() Function:
Accesses data from a subsequent row within the same result set.
LAG() Function:
Accesses data from a preceding row within the same result set.
PARTITION BY Clause:
Divides the result set into partitions to which the window function is applied.
FIRST_VALUE() Function:
Returns the first value in an ordered set of values.
LAST_VALUE() Function:
Returns the last value in an ordered set of values.
NTH_VALUE() Function:
Returns the nth value in an ordered set of values.
HAVING COUNT() > 1:
Filters groups based on having more than one occurrence.
CASCADE Option in DELETE:
Deletes all rows in child tables when a record in the parent table is deleted.
SET NULL Option in DELETE:
Sets foreign key columns to NULL in child tables when a record in the parent table is deleted.
SET DEFAULT Option in DELETE:
Sets foreign key columns to their default values in child tables when a record in the parent table is deleted.
CASCADE Option in UPDATE:
Updates foreign key values in child tables when a record in the parent table is updated.
SET NULL Option in UPDATE:
Sets foreign key columns to NULL in child tables when a record in the parent table is updated.
SET DEFAULT Option in UPDATE:
Sets foreign key columns to their default values in child tables when a record in the parent table is updated.
FOR UPDATE Clause:
Locks rows selected for update, preventing other users from modifying them.
FOR SHARE Clause:
Locks rows selected for read, preventing other users from updating or deleting them.
UNION ALL Operator:
Combines the result sets of two or more SELECT statements, including duplicates.
CHECK Constraint:
Ensures that values in a column meet specific conditions.
PRIMARY KEY Constraint:
Enforces the uniqueness of values in a column or a set of columns.
FOREIGN KEY Constraint:
Establishes a link between data in two tables, preventing actions that would destroy the link.
DEFAULT Constraint:
Provides a default value for a column when no value is specified.
INDEX:
Improves the speed of data retrieval operations on a database table.
CREATE VIEW Statement:
Creates a virtual table based on the result set of a SELECT statement.
CREATE INDEX Statement:
Creates an index on a table.
ALTER INDEX Statement:
Modifies an existing index.
DROP INDEX Statement:
Removes an index from a table.
TRANSACTION:
A sequence of one or more SQL statements treated as a single unit of work.
COMMIT Statement:
Saves changes made during the current transaction.
ROLLBACK Statement:
Undoes changes made during the current transaction.
SAVEPOINT Statement:
Sets a point within a transaction to which you can later roll back.
ROLLBACK TO SAVEPOINT Statement:
Undoes all changes made since a specified savepoint was established.
SET TRANSACTION ISOLATION LEVEL:
Sets the isolation level for the current transaction.
UNIQUE Constraint:
Ensures that all values in a column or a set of columns are unique.
JOIN Clause:
Combines rows from two or more tables based on a related column.
EXISTS Operator:
Tests for the existence of any records in a subquery.
NOT EXISTS Operator:
Tests for the non-existence of any records in a subquery.
ANY Operator:
Compares a value to any value in a list or a subquery.
ALL Operator:
Compares a value to all values in a list or a subquery.
CASE Expression:
Performs conditional logic within a SELECT statement.
COALESCE() Function:
Returns the first non-NULL value in a list.
NULLIF() Function:
Returns NULL if two expressions are equal; otherwise, returns the first expression.
CURRENT_USER Function:
Retrieves the current user.
SESSION_USER Function:
Retrieves the session user.
DATABASE() Function:
Retrieves the current database name.
LIMIT Clause:
Specifies the number of rows to return in a result set.
OFFSET Clause:
Specifies the number of rows to skip before starting to return rows.
FETCH FIRST n ROWS ONLY Clause:
Limits the number of rows returned in a result set.
FETCH NEXT n ROWS ONLY Clause:
Retrieves the next n rows from a result set.
FETCH LAST n ROWS ONLY Clause: – Retrieves the last n rows from a result set.
These SQL formulas cover a wide range of functionalities within SQL. If you have specific areas of interest or if you need more examples in a particular category, feel free to let me know!
