Structuring data and querying it, from single-table reads to architecture and standards work.
Working with SQL and databases means deciding how data gets stored and how you get it back out. You start with single-table lookups, then move to queries that join several tables. Next come schemas drawn from real requirements, tuning that starts with an execution plan, and architecture calls that split transaction processing from analytics. What separates the levels isn't fluency with one product's features. It's whether you can explain why you chose that structure and that storage technology.
You've just started working with databases. You understand that a table is rows and columns, and that every column carries a data type. Conditions and sorting get you the rows you want. You also know a missing value won't turn up under a normal comparison. Working across several tables at once is still out of reach.
What Comes Next
If you've checked off most of this list, you're ready for the Data Retriever stage, writing queries that link tables together. A relational database gets its power from storing data in separate tables and stitching them back together on demand.
The ladder from SQLD (two subjects covering data modeling concepts plus SQL basics and application) to SQLP (three subjects adding advanced application and tuning, with 2 practical questions), together with the 40% per-subject failing threshold, grounds the level boundaries in this guide.
Describes observable behavior at each responsibility level, from Level 2 (assisting with design under supervision) to Level 5 (advising on DBMS selection and tuning transactional and analytical platforms together). Direct evidence behind the checklist items at every level.
The standard textbook for university database courses. The official author site publishes the table of contents, online chapters, and a practice SQL tool for free, which sets an authoritative learning order running from the relational model through transactions and query optimization.
Sorts 18 families of SQL error found in over 33,000 queries submitted by 237 students into syntax, semantic and logical classes. The novice error types it names, comparison with NULL, omitted joins, and illegal or insufficient grouping, are direct evidence for the Lv.1 and Lv.2 checklist items.
