SQL

SQL SELECT & WHERE — Filtering, Operators, NULL Handling

College · priority 1

sqlselectwherenulloperators

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

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sqljoinsinnerleftrightanti-join

GROUP BY & HAVING — Aggregations, Filters on Aggregates

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sqlgroup-byhavingaggregatescountsumavg

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

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sqlwindow-functionsrow_numberranklagleadpartition

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

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sqlcterecursivewithhierarchygraph

PIVOT / UNPIVOT & Conditional Aggregates for Reporting

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sqlpivotunpivotcase-whenreport

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

College · priority 1

sqlexplainquery-planoptimizerhash-joinnested-loop

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

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sqlindexb-treegingistpartial-indexcovering

Execution Statistics — pg_stat_statements / Slow Query Log Triage

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sqlstatspg_statslow-query-logtriagehotspots

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

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sqltransactionsisolationserializablesnapshotacid

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

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sqldeadlocklockingskip-lockedadvisory-lock

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

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sqlupsertmergeon-conflictidempotentrace-condition

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

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sqlbulkcopyload-datastagingbatch

JSON / JSONB Operators — Querying, Indexing, Path Operators

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sqljsonjsonb@>->jsonpathgin-index

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

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sqlarrayrangeunnestoverlapsexclusion-constraint

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

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sqlfull-texttsvectortsqueryginranking

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

College · priority 1

sqlpartitioningrangelisthashpruningdeclarative

Materialized Views — REFRESH Strategies, Incremental Patterns

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sqlmaterialized-viewrefreshconcurrentlyincremental

Triggers & Stored Procedures — Audit Trails / Guard Rails

College · priority 1

sqltriggerstored-procedureplpgsqlaudit

Row-Level Security — Multi-Tenant Isolation with Policies

College · priority 1

sqlrlsmulti-tenantpolicysecuritypostgres

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

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sqlauthenticationidentityrbacsessionjwt

Audit & Change Data Capture — Debezium / Logical Replication

College · priority 1

sqlcdcdebeziumlogical-replicationaudit-logkafka

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

College · priority 1

sqlonline-ddlgh-ostpt-osczero-downtimemigration

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

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sqlbackuppitrwalpgbackrestbarmandisaster-recovery

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

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sqlreplicationstreaminglogicalpatronifailover

Connection Pooling — PgBouncer / RDS Proxy / Transaction vs Session

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sqlpoolingpgbouncerrds-proxytransaction-mode

Slow Query Triage — auto_explain / pg_stat_activity / Locks View

College · priority 1

sqlslow-queryauto-explainpg_stat_activitylocks

Analytical Functions in Warehouses — Snowflake / BigQuery / Redshift

College · priority 1

sqlwarehousesnowflakebigqueryredshiftanalytics