Certainly! Here are 25 SQL tricks for beginners:
SELECT Statement: Retrieve data from a database table using the SELECT statement.
WHERE Clause: Filter data based on specific conditions using the WHERE clause in conjunction with the SELECT statement.
DISTINCT Keyword: Retrieve unique values from a column using the DISTINCT keyword.
ORDER BY Clause: Sort the result set in ascending or descending order using the ORDER BY clause.
LIMIT Clause: Limit the number of rows returned by a query using the LIMIT clause (syntax may vary across different database systems).
JOIN: Combine rows from multiple tables based on a related column using JOIN operations such as INNER JOIN, LEFT JOIN, RIGHT JOIN, or FULL JOIN.
GROUP BY Clause: Group rows based on a specific column(s) and perform aggregate functions like COUNT, SUM, AVG, MAX, or MIN on grouped data.
HAVING Clause: Filter the result set based on conditions applied to the groups created by the GROUP BY clause.
INSERT Statement: Insert new data into a table using the INSERT statement.
UPDATE Statement: Modify existing data in a table using the UPDATE statement.
DELETE Statement: Remove data from a table using the DELETE statement.
IN Operator: Check if a value exists within a set of values using the IN operator.
BETWEEN Operator: Check if a value falls within a specific range using the BETWEEN operator.
LIKE Operator: Perform pattern matching using the LIKE operator with wildcard characters (% and _).
NULL Values: Handle NULL values in the database using IS NULL or IS NOT NULL operators.
COUNT() Function: Count the number of rows in a table or the number of occurrences of a specific value using the COUNT() function.
SUM() Function: Calculate the sum of values in a column using the SUM() function.
AVG() Function: Calculate the average of values in a column using the AVG() function.
MAX() Function: Retrieve the maximum value from a column using the MAX() function.
MIN() Function: Retrieve the minimum value from a column using the MIN() function.
Alias: Assign a temporary name to a table or column using the AS keyword to improve readability.
Subqueries: Use a query within another query to perform complex operations or retrieve data from multiple tables.
EXISTS Keyword: Check the existence of specific data in a subquery using the EXISTS keyword.
UNION Operator: Combine the result sets of multiple SELECT statements into a single result set using the UNION operator.
CASE Statement: Perform conditional logic within a query using the CASE statement to create custom columns or apply specific operations based on conditions.
Top comments (2)
Really cool, it is really helpful for beginners I think. Did you know that
IN(value1,value2)is the same has=ANY(ARRAY[value1,value2]). Actually when you look at the execution plan this what it is displayThe article can be improved by examples for each statement.
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