From T-SQL fundamentals to storage engine internals — a structured 5-phase learning path for developers who want to truly understand SQL Server, not just write queries that happen to work.
How SQL Server actually processes a query: logical order (FROM→WHERE→GROUP BY→SELECT→ORDER BY), NULLs, 3-valued logic.
Read guide →Every join type explained with execution plan impact, NULL behaviour, and when to use each for performance.
Read guide →Common Table Expressions, recursive CTEs for hierarchies, derived tables vs views vs temp tables.
Read guide →Advanced aggregation: multi-dimensional grouping with ROLLUP/CUBE, dynamic PIVOT/UNPIVOT, and MERGE.
Read guide →Ranking functions explained with pagination, deduplication, and top-N-per-group patterns.
Read guide →SUM/AVG OVER(), running totals, cumulative distributions, and 30-day rolling calculations.
Read guide →Precise frame control for YTD, rolling 12-month, and cumulative calculations.
Read guide →Offset functions for comparing rows: period-over-period change, gap detection, and churn analysis.
Read guide →Eliminate row-by-row processing: CROSS APPLY, OUTER APPLY, and set-based rewrites with benchmarks.
Read guide →JSON_VALUE/JSON_QUERY, system-versioned temporal tables for audit trails, STRING_AGG, and sequences.
Read guide →Graphical plans, estimated vs actual rows, cost percentages, operator tooltips, and the 2-minute read method.
Read guide →When SQL Server picks each join algorithm, cost thresholds, and how to force a better choice.
Read guide →Every warning type explained with root cause and fix — implicit conversions, memory spills, and missing stats.
Read guide →Choosing the right index type, column order, included columns, and measuring index effectiveness.
Read guide →How indexes are stored, why page splits hurt performance, and building a maintenance strategy.
Read guide →Histograms, density vectors, auto-update thresholds, and when outdated statistics cause bad plans.
Read guide →Reproduce parameter sniffing, identify it in the plan cache, and fix with RECOMPILE, optimize for, or plan guides.
Read guide →Top 10 wait types decoded: CXPACKET, LCK_M, PAGEIOLATCH, SOS_SCHEDULER_YIELD and what they mean.
Read guide →sys.dm_exec_requests, deadlock graph XML analysis, Extended Events tracing, and prevention strategies.
Read guide →TempDB contention, PAGELATCH waits, version store growth, worktable spills, and multi-file configuration.
Read guide →8KB pages anatomy, IAM pages, heap vs clustered table trade-offs, and reading raw pages with DBCC PAGE.
Read guide →Write-Ahead Logging, VLFs, checkpoint types, log reuse wait reasons, and recovery models explained.
Read guide →S, X, U, IS, IX lock types, escalation thresholds, NOLOCK dangers, and Read Committed Snapshot Isolation.
Read guide →Dirty reads, phantom reads, non-repeatable reads — which isolation level prevents which, with demos.
Read guide →Buffer pool management, plan cache bloat with sys.dm_exec_cached_plans, and resolving OOM conditions.
Read guide →Columnstore architecture, batch mode execution, delta store management, and analytics query acceleration.
Read guide →Read execution plans, fix 5 damaging query patterns (implicit conversions, functions on indexed columns, SELECT *, non-SARGable LIKE, scalar UDFs), build covering and filtered indexes, use Query Store to catch regressions, and 10 quick wins you can apply today.
Read guide →RPO/RTO defined per criticality tier, recovery models explained, robust backup scripts with COMPRESSION+CHECKSUM, point-in-time restore with STOPAT, Ola Hallengren setup, Azure Blob backup, and step-by-step DR scenarios for server loss and accidental table drop.
Read guide →Complete T-SQL setup from scratch (endpoints, CREATE AVAILABILITY GROUP, listener), readable secondaries with routing, health dashboard DMV queries, planned and forced failover, rolling patching pattern, and Basic AG vs Enterprise AG comparison.
Read guide →12 assessment factors, 4 migration strategies (in-place, backup/restore, log shipping, AG), zero-data-loss tail-log technique, 20-check post-restore validation suite, Query Store regression monitoring, rollback plan, 10 common post-migration problems, and a DemoBank Finance case study (SQL Server 2014 → 2019, 3-hour window, zero data loss).
Read guide →A five-part case study following a real-world migration of a UK asset finance company from Progress OpenEdge 4GL to SQL Server 2019. Covers the full DDL, COBOL VISION constraints, application-managed relationships, migration strategy, and modernisation results. Targets senior DBAs, finance-sector consultants, and 4GL migration specialists.
Full 18-table DDL for an 85,000-contract HP and Lease system. COBOL VISION rules: CHAR fields, INT dates, app-managed sequences, no FK constraints.
Read case study →The three COBOL copybooks, fixed-length record mapping, and the T-SQL validation procedure that stops corrupt VISION file exports before they happen.
Read case study →The 4 RI patterns Progress 4GL used instead of FK constraints, all 10 orphan audit queries, remediation strategies, and a phased plan for safely adding FK constraints post-migration.
Read case study →Five-phase plan, SSIS staging pipeline, 90-day parallel run with 7 reconciliation failures, 23-check cutover weekend, and the 3 Month-1 production incidents.
Read case study →Hard numbers: 4-hour report → 3.5 min (67×), £152K annual saving, 2 FCA findings closed, 2.8-year payback. Plus the three things that did not improve and the six lessons every 4GL migration needs.
Read case study →