Oracle SQL Foundations: Queries, Functions & Single-Row Logic
Work through real Oracle SQL on a fictional HR table: SELECT and DUAL, NULL handling with NVL, NVL2 and COALESCE, text, number and date functions, TO_CHAR and TO_DATE, CASE and DECODE, ROWNUM and FETCH FIRST and sequences, with every answer checked as you go.
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About this course
Oracle SQL Foundations teaches you to read and predict real Oracle queries. You work with the fictional HR table of a logistics company and in every lab you work out exactly what a query returns: calculated columns and DUAL, how NULL behaves in filters, sorting and arithmetic, and how NVL, NVL2, COALESCE and NULLIF fix it. You use character functions like SUBSTR, INSTR and LPAD, round and truncate numbers, calculate with dates, format results with TO_CHAR, convert text with TO_DATE, write CASE and DECODE logic, build top-N queries with FETCH FIRST, avoid the ROWNUM traps and trace a sequence. A final report project ties it all together. Every answer is checked instantly, and the first lesson is free.
Lessons
- SELECT, Arithmetic and Column AliasesFree
- DUAL, Bind Variables and Operator Precedence Locked
- Column Aliases, Quotes and DISTINCT Locked
- WHERE: Comparisons, BETWEEN, IN and LIKE Locked
- ORDER BY and Where the NULLs Go Locked
- NULL: Unknown Values in Filters and Arithmetic Locked
- NVL: Replacing NULL Before It Breaks Your Totals Locked
- NVL2: Different Results for NULL and Not NULL Locked
- COALESCE and NULLIF Locked
- Concatenation with || and CONCAT Locked
- Character Functions: SUBSTR, INSTR, LENGTH and Case Locked
- LPAD, RPAD, TRIM and REPLACE Locked
- Number Functions: ROUND, TRUNC, CEIL, FLOOR, MOD Locked
- SYSDATE and Date Arithmetic Locked
- MONTHS_BETWEEN, ADD_MONTHS, LAST_DAY and NEXT_DAY Locked
- TRUNC, ROUND and EXTRACT on Dates Locked
- TO_CHAR with Dates: Format Models Locked
- TO_CHAR with Numbers: Formats, FM and #### Locked
- TO_DATE, Date Literals and Implicit Conversion Locked
- CASE and DECODE: If-Then Logic in a Query Locked
- Top-N Queries: FETCH FIRST, OFFSET and ROWNUM Locked
- Sequences: NEXTVAL, CURRVAL and Gaps Locked
- Final Project: An HR Report Query Locked