https://sqlpractice.co.in/ Free SQL tutorials with runnable examples: SELECT, JOINs, GROUP BY, CTEs, window functions and interview preparation. en Fri, 11 Sep 2026 06:38:42 GMT https://sqlpractice.co.in/blog/sql-views.html https://sqlpractice.co.in/blog/sql-views.html What a view is, how CREATE VIEW works, why it does not make queries faster, when a view is updatable, and how a materialized view differs - with runnable examples. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-union-vs-union-all.html https://sqlpractice.co.in/blog/sql-union-vs-union-all.html UNION removes duplicate rows and UNION ALL keeps them. What that costs, the column rules both must obey, where ORDER BY goes, and why UNION ALL is the right default. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-second-highest-salary.html https://sqlpractice.co.in/blog/sql-second-highest-salary.html Five ways to find the second highest salary in SQL - subquery, LIMIT OFFSET, correlated count, DENSE_RANK and CTE - plus the Nth highest and ties. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-primary-key-vs-foreign-key.html https://sqlpractice.co.in/blog/sql-primary-key-vs-foreign-key.html A primary key identifies a row; a foreign key points at one. How they differ in uniqueness, NULLs and count - plus composite keys and ON DELETE. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-order-by-limit.html https://sqlpractice.co.in/blog/sql-order-by-limit.html How ORDER BY sorts - several columns, expressions, aliases, NULL placement - and how LIMIT with OFFSET gives you top-N results and pagination. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-normalization.html https://sqlpractice.co.in/blog/sql-normalization.html Normalization explained by fixing one badly designed table step by step - first normal form, second, third - plus what denormalization is for and when to stop. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-indexes.html https://sqlpractice.co.in/blog/sql-indexes.html What an index actually is, how CREATE INDEX works, which columns to index, why composite column order matters, and the mistakes that stop an index being used at all. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-find-duplicates.html https://sqlpractice.co.in/blog/sql-find-duplicates.html Find duplicate rows in SQL with GROUP BY and HAVING, see every copy rather than the counts, and delete the extras while keeping one - safely. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-distinct-guide.html https://sqlpractice.co.in/blog/sql-distinct-guide.html How SELECT DISTINCT works, why it applies to the whole row and not one column, DISTINCT with several columns, COUNT(DISTINCT), and when GROUP BY is the better tool. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-delete-truncate-drop.html https://sqlpractice.co.in/blog/sql-delete-truncate-drop.html DELETE removes chosen rows, TRUNCATE empties a table, DROP removes the table. What each logs and resets, which can be rolled back, and how to choose. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-constraints.html https://sqlpractice.co.in/blog/sql-constraints.html NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK and DEFAULT explained with the exact errors they produce - and why they belong in the database. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-commands-ddl-dml-dcl-tcl.html https://sqlpractice.co.in/blog/sql-commands-ddl-dml-dcl-tcl.html Every SQL statement belongs to one of four families - DDL, DML, DCL and TCL. What each does, which can be rolled back, and why implicit commits matter. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-aggregate-functions.html https://sqlpractice.co.in/blog/sql-aggregate-functions.html COUNT, SUM, AVG, MIN and MAX with runnable examples: COUNT(*) vs COUNT(column), how NULLs are skipped, and why WHERE cannot filter an aggregate. Thu, 10 Sep 2026 18:28:03 +0530 https://sqlpractice.co.in/blog/sql-for-data-analysts.html https://sqlpractice.co.in/blog/sql-for-data-analysts.html The SQL a working data analyst uses every day: filtering, grouping, joins, conditional aggregation, cohorts and running totals - with runnable examples and the mistakes that quietly corrupt reports. Fri, 4 Sep 2026 10:36:16 +0530 https://sqlpractice.co.in/blog/sql-exercises-with-solutions.html https://sqlpractice.co.in/blog/sql-exercises-with-solutions.html Fifteen SQL practice problems with full solutions and explanations, from a first SELECT to multi-step reports. Every solution runs on a live sample database you can open in one click. Fri, 4 Sep 2026 03:20:10 +0530 https://sqlpractice.co.in/blog/sql-dialect-differences.html https://sqlpractice.co.in/blog/sql-dialect-differences.html The SQL differences that actually bite when you switch databases: LIMIT vs TOP, quoting, string concatenation, dates, booleans, auto-increment keys, upserts and window-function support, side by side. Fri, 4 Sep 2026 03:20:10 +0530 https://sqlpractice.co.in/blog/sql-window-functions.html https://sqlpractice.co.in/blog/sql-window-functions.html What window functions do, how ROW_NUMBER, RANK, DENSE_RANK and PARTITION BY differ, and the top-N-per-group pattern interviews often ask for. Sat, 29 Aug 2026 06:40:12 +0530 https://sqlpractice.co.in/blog/sql-data-analyst-interview-questions.html https://sqlpractice.co.in/blog/sql-data-analyst-interview-questions.html Ten business-scenario SQL questions of the kind data analyst interviews actually ask, each with a runnable solution and the reasoning an interviewer wants to hear. Sat, 29 Aug 2026 06:40:12 +0530 https://sqlpractice.co.in/blog/sql-cheat-sheet.html https://sqlpractice.co.in/blog/sql-cheat-sheet.html A free, single-page SQL cheat sheet — SELECT, JOINs, WHERE operators, aggregate functions, GROUP BY, and the real query execution order, with runnable examples. Wed, 26 Aug 2026 15:11:52 +0530 https://sqlpractice.co.in/blog/sql-where-clause-guide.html https://sqlpractice.co.in/blog/sql-where-clause-guide.html A complete guide to the SQL WHERE clause: comparison operators, AND/OR/NOT, IN, BETWEEN, LIKE, and IS NULL, with runnable examples. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-subqueries-guide.html https://sqlpractice.co.in/blog/sql-subqueries-guide.html Scalar, row, and correlated subqueries in SQL explained with examples, plus when a JOIN is the better tool instead. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-string-functions.html https://sqlpractice.co.in/blog/sql-string-functions.html The core SQL string functions — UPPER, LOWER, LEN, SUBSTRING, REPLACE, TRIM, CONCAT, COALESCE and NULLIF — explained with runnable examples and dialect notes. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-select-statement-guide.html https://sqlpractice.co.in/blog/sql-select-statement-guide.html Learn the SQL SELECT statement from scratch: column lists, aliases, DISTINCT, ORDER BY, and LIMIT, with examples you can run instantly in the browser. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-joins-explained.html https://sqlpractice.co.in/blog/sql-joins-explained.html A clear, table-by-table walkthrough of INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN in SQL, with runnable examples. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-interview-questions.html https://sqlpractice.co.in/blog/sql-interview-questions.html 25 commonly asked SQL interview questions with clear answers — from WHERE vs HAVING to window functions, normalization, and finding duplicate rows. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-insert-update-delete.html https://sqlpractice.co.in/blog/sql-insert-update-delete.html How to add, change and remove rows in SQL — and the SELECT-first habit that stops a missing WHERE clause from destroying a table. Runnable examples included. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-exists-vs-in.html https://sqlpractice.co.in/blog/sql-exists-vs-in.html How EXISTS and IN differ, why NOT IN breaks on NULL while NOT EXISTS does not, when a JOIN is better than either, and how to choose - with runnable examples. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-date-functions.html https://sqlpractice.co.in/blog/sql-date-functions.html The date functions real queries use — YEAR, MONTH, DAY, DATEDIFF — plus the safe date-range pattern that avoids the classic BETWEEN bug. Runnable examples. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-cte-with-clause.html https://sqlpractice.co.in/blog/sql-cte-with-clause.html What a Common Table Expression is, why WITH beats nested subqueries for readable multi-step queries, and how to chain several CTEs — with runnable examples. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/sql-case-when.html https://sqlpractice.co.in/blog/sql-case-when.html How SQL CASE expressions work: searched vs simple CASE, custom sort orders, counting and summing by condition — with runnable examples. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/how-to-write-sql-queries.html https://sqlpractice.co.in/blog/how-to-write-sql-queries.html Never written SQL before? This step-by-step guide starts from zero — what a table is, your first query, filtering, sorting, and more — with examples you can run instantly. Tue, 18 Aug 2026 08:36:02 +0530 https://sqlpractice.co.in/blog/group-by-vs-having.html https://sqlpractice.co.in/blog/group-by-vs-having.html The clear, memorable explanation of GROUP BY vs HAVING in SQL, why WHERE can't filter aggregates, and worked examples. Tue, 18 Aug 2026 08:36:02 +0530