Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →

menu_book Course Curriculum (SQL) expand_more

Relational Foundations

SELECT literals Column aliases DISTINCT rows ORDER BY LIMIT and OFFSET NULL semantics Three-valued logic CASE expressions COALESCE NULLIF

Filtering

WHERE predicates Comparison operators BETWEEN IN lists LIKE patterns ESCAPE in LIKE IS NULL Boolean combinations Operator precedence EXISTS

Aggregation

COUNT SUM AVG MIN and MAX GROUP BY HAVING Conditional aggregation Grouping expressions COUNT DISTINCT Aggregate NULL behavior

Joins

INNER JOIN LEFT JOIN RIGHT JOIN FULL OUTER JOIN CROSS JOIN Self join Non-equi join Composite join keys Join filtering Anti join with NOT EXISTS

Subqueries & Sets

Scalar subquery Correlated subquery Derived table CTE Recursive CTE UNION UNION ALL INTERSECT EXCEPT Subquery with ANY Subquery with ALL

Window Functions

ROW_NUMBER RANK DENSE_RANK PARTITION BY Window ORDER BY ROWS frame RANGE frame LAG LEAD Running total

Data Changes

INSERT Multi-row INSERT INSERT SELECT UPDATE UPDATE with subquery DELETE MERGE Transactions SAVEPOINT ROLLBACK

Schema & Integrity

CREATE TABLE PRIMARY KEY FOREIGN KEY UNIQUE constraint CHECK constraint DEFAULT values ALTER TABLE CREATE INDEX Composite index VIEW

SQL / Relational Foundations

SELECT literals

Learn SELECT literals in SQL through a focused explanation, a dedicated construct-specific example, an engineering boundary, and a mastery check.

10 min read • Beginner

SELECT literals is an atomic SQL topic inside Relational Foundations. This lesson focuses on how the SELECT literals construct is written, what it changes, and when it is the right tool.

Trace the example line by line. Identify the exact syntax for SELECT literals, the input state before it runs, and the resulting value, control flow, database state, hardware behavior, or runtime effect afterward. Neighboring lessons use different constructs rather than renamed copies of this one.

Topic-specific example

sql-01-01-select-literals.sql

sql Try It Live

SELECT 42 AS answer, 'ready' AS status;

Edge case / engineering note

For SELECT literals, test the boundary that belongs to this exact feature rather than a generic failure case. Check invalid or empty input, NULL/unknown state, numeric limits, transaction or exception behavior, synthesis/runtime constraints, ownership/permission rules, or backtracking/control-flow effects where they apply.

Content source & attribution

Original Syntaxis Content · Original Syntaxis Content

Practice checkpoint

Test what you learned

Find Department Top Earners with DENSE_RANK

25 XP · Intermediate

Calculate 7-Day User Retention Cohort

30 XP · Advanced

Second Highest Salary Without Window Functions (Variation #1)

15 XP · Intermediate

Second Highest Salary Without Window Functions (Variation #2)

20 XP · Intermediate

Second Highest Salary Without Window Functions (Variation #3)

25 XP · Intermediate

Second Highest Salary Without Window Functions (Variation #4)

30 XP · Intermediate

Delete Duplicate Emails Retaining Smallest ID (Variation #1)

15 XP · Beginner

Delete Duplicate Emails Retaining Smallest ID (Variation #2)

20 XP · Beginner

Delete Duplicate Emails Retaining Smallest ID (Variation #3)

25 XP · Beginner

Delete Duplicate Emails Retaining Smallest ID (Variation #4)

30 XP · Beginner

Calculate Running Total with SUM() OVER() (Variation #1)

15 XP · Intermediate

Calculate Running Total with SUM() OVER() (Variation #2)

20 XP · Intermediate

Calculate Running Total with SUM() OVER() (Variation #3)

25 XP · Intermediate

Calculate Running Total with SUM() OVER() (Variation #4)

30 XP · Intermediate

Lesson quizzes

SELECT literals Mastery Check →