SQL

SQL SELECT & WHERE — Filtering, Operators, NULL Handling

Professional · priority 1

sqlselectwherenulloperators

SQL Joins — INNER / LEFT / RIGHT / FULL + Anti-Joins

Professional · priority 1

sqljoinsinnerleftrightanti-join

GROUP BY & HAVING — Aggregations, Filters on Aggregates

Professional · priority 1

sqlgroup-byhavingaggregatescountsumavg

Window Functions — ROW_NUMBER / RANK / LAG / LEAD / SUM OVER

Professional · priority 1

sqlwindow-functionsrow_numberranklagleadpartition

CTEs & Recursive Queries — WITH Clause / Hierarchies / Graph Walks

Professional · priority 1

sqlcterecursivewithhierarchygraph

PIVOT / UNPIVOT & Conditional Aggregates for Reporting

Professional · priority 1

sqlpivotunpivotcase-whenreport

Query Optimization — EXPLAIN ANALYZE / Hash vs Merge vs Nested Loop

Professional · priority 1

sqlexplainquery-planoptimizerhash-joinnested-loop

Indexing Strategies — B-Tree / Hash / GIN / GiST / Partial / Covering

Professional · priority 1

sqlindexb-treegingistpartial-indexcovering

Execution Statistics — pg_stat_statements / Slow Query Log Triage

Professional · priority 1

sqlstatspg_statslow-query-logtriagehotspots

Transactions & Isolation Levels — RR / RC / Serializable / Snapshot

Professional · priority 1

sqltransactionsisolationserializablesnapshotacid

Deadlocks & Locking — Detection, Retry, Lock-Ordering Discipline

Professional · priority 1

sqldeadlocklockingskip-lockedadvisory-lock

UPSERT / MERGE / ON CONFLICT — Idempotent Writes & Race Safety

Professional · priority 1

sqlupsertmergeon-conflictidempotentrace-condition

Bulk Load — COPY / LOAD DATA / External Tables / Staging Patterns

Professional · priority 1

sqlbulkcopyload-datastagingbatch

JSON / JSONB Operators — Querying, Indexing, Path Operators

Professional · priority 1

sqljsonjsonb@>->jsonpathgin-index

Arrays & Range Types — Unnesting, Overlaps, Inclusive/Exclusive

Professional · priority 1

sqlarrayrangeunnestoverlapsexclusion-constraint

Full-Text Search — tsvector / tsquery / ts_rank / Dictionary Configs

Professional · priority 1

sqlfull-texttsvectortsqueryginranking

Table Partitioning — RANGE / LIST / HASH / Sub-Partitioning

Professional · priority 1

sqlpartitioningrangelisthashpruningdeclarative

Materialized Views — REFRESH Strategies, Incremental Patterns

Professional · priority 1

sqlmaterialized-viewrefreshconcurrentlyincremental

Triggers & Stored Procedures — Audit Trails / Guard Rails

Professional · priority 1

sqltriggerstored-procedureplpgsqlaudit

Row-Level Security — Multi-Tenant Isolation with Policies

Professional · priority 1

sqlrlsmulti-tenantpolicysecuritypostgres

Authentication & Identity Schema — Users, Roles, Sessions, Tokens

Professional · priority 1

sqlauthenticationidentityrbacsessionjwt

Audit & Change Data Capture — Debezium / Logical Replication

Professional · priority 1

sqlcdcdebeziumlogical-replicationaudit-logkafka

Online Schema Change — Zero-Downtime DDL / gh-ost / pt-osc

Professional · priority 1

sqlonline-ddlgh-ostpt-osczero-downtimemigration

Backup & PITR — pg_basebackup / WAL Archiving / Barman / pgBackRest

Professional · priority 1

sqlbackuppitrwalpgbackrestbarmandisaster-recovery

Replication & HA — Streaming / Logical / Patroni / Failover Drills

Professional · priority 1

sqlreplicationstreaminglogicalpatronifailover

Connection Pooling — PgBouncer / RDS Proxy / Transaction vs Session

Professional · priority 1

sqlpoolingpgbouncerrds-proxytransaction-mode

Slow Query Triage — auto_explain / pg_stat_activity / Locks View

Professional · priority 1

sqlslow-queryauto-explainpg_stat_activitylocks

Analytical Functions in Warehouses — Snowflake / BigQuery / Redshift

Professional · priority 1

sqlwarehousesnowflakebigqueryredshiftanalytics