SQL - PostgreSQL: Execution Order
Mind map detailing the execution order of clauses in SQL, used in the article: “SQL - PostgreSQL: Execution Order” on GitHub.
1. FROM
1.1. JOINs
1.1.1. LEFT
1.1.1.1. INNER
1.1.1.1.1. TABLE LEFT (TL)
1.1.2. INNER
1.1.2.1. T1 LEFT
1.1.2.1.1. EMPTY LINES TR = NULL
1.1.2.2. T1 RIGHT
1.1.2.2.1. EMPTY LINES = NULL
1.1.3. RIGHT
1.1.3.1. INNER
1.1.3.1.1. TABLE RIGHT (TR)
1.1.4. FULL
1.1.4.1. RIGHT
1.1.4.1.1. FULL LINES
1.1.4.2. LEFT
1.1.4.2.1. FULL LINES
2. WHERE
2.1. LINES
2.1.1. FROM
2.1.1.1. HAVING
2.1.2. JOINs
2.1.2.1. HAVING
2.2. COMPARISON OPERATORS
2.2.1. =, ! = or < >, >, <, > =, < =, IN, BETWEEN, LIKE, IS NULL
2.3. GROUP BY
2.3.1. HAVING
2.3.1.1. COUNT()
2.3.1.2. SUM()
2.3.1.3. MAX()
2.3.1.4. MIN()
2.3.1.5. AVG()
3. GROUP BY
3.1. UNAGGREGATED COLUMNS (SELECT)
3.2. HAVING
4. SELECT
4.1. DISTINCT
4.2. COLUMNS
4.3. AS (COLUMNS)
4.4. AGGREGATE FUNCTIONS
4.4.1. COUNT(), SUM(), AVG(), MAX(), MIN()
5. ORDER BY
5.1. ASC
5.1.1. WHERE
5.1.1.1. GROUP BY
5.1.1.1.1. HAVING
5.2. DESC
5.2.1. WHERE
5.2.1.1. GROUP BY
5.2.1.1.1. HAVING
6. LIMIT
6.1. LINES
6.1.1. ORDER BY