Esta seção tem por objetivo delinear até que ponto o PostgreSQL está em conformidade com o padrão SQL. A conformidade total com o padrão, ou uma declaração completa sobre a conformidade com o padrão, é complicada e não é particularmente útil. Portanto, esta seção só pode mostrar uma visão geral.
O nome formal do padrão SQL é ISO/IEC 9075 "Database Language SQL". A versão revisada do padrão é liberada de tempos em tempos; a mais recente surgiu em 1999. Esta versão é referida como ISO/IEC 9075:1999 ou, informalmente, como SQL:1999. A versão anterior a esta foi a SQL-92. O desenvolvimento do PostgreSQL tenta manter a conformidade com a última versão oficial do padrão, quando esta conformidade não contradiz as funcionalidades tradicionais ou o senso comum. Quando este texto foi escrito, uma votação se encontrava em andamento para realizar uma nova revisão do padrão, a qual, se aprovada, se tornará algum dia a referência de conformidade para o desenvolvimento das versões futuras do PostgreSQL.
O SQL-92 definiu três conjuntos de funcionalidades para conformidade: Entrada, Intermediário e Completo. A maioria dos sistemas gerenciadores de banco de dados que se declaravam em conformidade com este padrão SQL, estavam em conformidade apenas com o nível de Entrada, porque o conjunto completo de funcionalidades nos níveis Intermediário e Completo era muito volumoso, ou conflitava com comportamentos legados.
O SQL:1999 define um conjunto maior de funcionalidades individuais, em vez dos três níveis grandes e ineficazes presentes no SQL-92. Um subconjunto grande destas funcionalidades representa as funcionalidades "núcleo" (core), que toda implementação em conformidade com o padrão SQL deve atender. As demais funcionalidades são inteiramente opcionais. Algumas funcionalidades opcionais são agrupadas para formarem "pacotes", com os quais as implementações SQL podem se declarar em conformidade, portanto se declarando em conformidade com um determinado grupo de funcionalidades.
O padrão SQL:1999 está dividido em 5 partes: Framework, Foundation, Call Level Interface, Persistent Stored Modules e Host Language Bindings. O PostgreSQL somente cobre as partes 1, 2 e 5. A parte 3 é semelhante à interface ODBC, e a parte 4 é semelhante à linguagem de programação PL/pgSQL, mas a conformidade exata não é pretendida em nenhum destes dois casos.
A seguir é fornecida uma lista das funcionalidades suportadas pelo PostgreSQL, seguida por uma lista de funcionalidades definidas no SQL:1999 ainda não são suportadas pelo PostgreSQL. As duas listas são aproximadas: podem existir pequenos detalhes que não estão em conformidade em uma funcionalidade declarada como suportada, enquanto grande parte de uma funcionalidade não suportada pode, na verdade, estar implementada. O corpo principal da documentação sempre contém informações mais precisas sobre o que funciona e que não funciona.
Nota: Os códigos de funcionalidade contendo hífen são subfuncionalidades. Portanto, se uma determinada subfuncionalidade não for suportada, a funcionalidade principal é declarada como não suportada, mesmo que outras subfuncionalidades sejam suportadas.
| Identificador | Pacote | Descrição | Comentário |
|---|---|---|---|
| B012 | Core | Embedded C | |
| B021 | Direct SQL | ||
| E011 | Core | Numeric data types | |
| E011-01 | Core | INTEGER and SMALLINT data types | |
| E011-02 | Core | REAL, DOUBLE PRECISION, and FLOAT data types | |
| E011-03 | Core | DECIMAL and NUMERIC data types | |
| E011-04 | Core | Arithmetic operators | |
| E011-05 | Core | Numeric comparison | |
| E011-06 | Core | Implicit casting among the numeric data types | |
| E021 | Core | Character data types | |
| E021-01 | Core | CHARACTER data type | |
| E021-02 | Core | CHARACTER VARYING data type | |
| E021-03 | Core | Character literals | |
| E021-04 | Core | CHARACTER_LENGTH function | |
| E021-05 | Core | OCTET_LENGTH function | |
| E021-06 | Core | SUBSTRING function | |
| E021-07 | Core | Character concatenation | |
| E021-08 | Core | UPPER and LOWER functions | |
| E021-09 | Core | TRIM function | |
| E021-10 | Core | Implicit casting among the character data types | |
| E021-11 | Core | POSITION function | |
| E021-12 | Core | Character comparison | |
| E031 | Core | Identifiers | |
| E031-01 | Core | Delimited identifiers | |
| E031-02 | Core | Lower case identifiers | |
| E031-03 | Core | Trailing underscore | |
| E051 | Core | Basic query specification | |
| E051-01 | Core | SELECT DISTINCT | |
| E051-02 | Core | GROUP BY clause | |
| E051-04 | Core | GROUP BY can contain columns not in <select list> | |
| E051-05 | Core | Select list items can be renamed | AS is required |
| E051-06 | Core | HAVING clause | |
| E051-07 | Core | Qualified * in select list | |
| E051-08 | Core | Correlation names in the FROM clause | |
| E051-09 | Core | Rename columns in the FROM clause | |
| E061 | Core | Basic predicates and search conditions | |
| E061-01 | Core | Comparison predicate | |
| E061-02 | Core | BETWEEN predicate | |
| E061-03 | Core | IN predicate with list of values | |
| E061-04 | Core | LIKE predicate | |
| E061-05 | Core | LIKE predicate ESCAPE clause | |
| E061-06 | Core | NULL predicate | |
| E061-07 | Core | Quantified comparison predicate | |
| E061-08 | Core | EXISTS predicate | |
| E061-09 | Core | Subqueries in comparison predicate | |
| E061-11 | Core | Subqueries in IN predicate | |
| E061-12 | Core | Subqueries in quantified comparison predicate | |
| E061-13 | Core | Correlated subqueries | |
| E061-14 | Core | Search condition | |
| E071 | Core | Basic query expressions | |
| E071-01 | Core | UNION DISTINCT table operator | |
| E071-02 | Core | UNION ALL table operator | |
| E071-03 | Core | EXCEPT DISTINCT table operator | |
| E071-05 | Core | Columns combined via table operators need not have exactly the same data type | |
| E071-06 | Core | Table operators in subqueries | |
| E081-01 | Core | SELECT privilege | |
| E081-02 | Core | DELETE privilege | |
| E081-03 | Core | INSERT privilege at the table level | |
| E081-04 | Core | UPDATE privilege at the table level | |
| E081-06 | Core | REFERENCES privilege at the table level | |
| E081-08 | Core | WITH GRANT OPTION | |
| E091 | Core | Set functions | |
| E091-01 | Core | AVG | |
| E091-02 | Core | COUNT | |
| E091-03 | Core | MAX | |
| E091-04 | Core | MIN | |
| E091-05 | Core | SUM | |
| E091-06 | Core | ALL quantifier | |
| E091-07 | Core | DISTINCT quantifier | |
| E101 | Core | Basic data manipulation | |
| E101-01 | Core | INSERT statement | |
| E101-03 | Core | Searched UPDATE statement | |
| E101-04 | Core | Searched DELETE statement | |
| E111 | Core | Single row SELECT statement | |
| E121-01 | Core | DECLARE CURSOR | |
| E121-02 | Core | ORDER BY columns need not be in select list | |
| E121-03 | Core | Value expressions in ORDER BY clause | |
| E121-04 | Core | OPEN statement | |
| E121-08 | Core | CLOSE statement | |
| E121-10 | Core | FETCH statement implicit NEXT | |
| E121-17 | Core | WITH HOLD cursors | |
| E131 | Core | Null value support (nulls in lieu of values) | |
| E141 | Core | Basic integrity constraints | |
| E141-01 | Core | NOT NULL constraints | |
| E141-02 | Core | UNIQUE constraints of NOT NULL columns | |
| E141-03 | Core | PRIMARY KEY constraints | |
| E141-04 | Core | Basic FOREIGN KEY constraint with the NO ACTION default for both referential delete action and referential update action | |
| E141-06 | Core | CHECK constraints | |
| E141-07 | Core | Column defaults | |
| E141-08 | Core | NOT NULL inferred on PRIMARY KEY | |
| E141-10 | Core | Names in a foreign key can be specified in any order | |
| E151 | Core | Transaction support | |
| E151-01 | Core | COMMIT statement | |
| E151-02 | Core | ROLLBACK statement | |
| E152 | Core | Basic SET TRANSACTION statement | |
| E152-01 | Core | SET TRANSACTION statement: ISOLATION LEVEL SERIALIZABLE clause | |
| E152-02 | Core | SET TRANSACTION statement: READ ONLY and READ WRITE clauses | |
| E161 | Core | SQL comments using leading double minus | |
| E171 | Core | SQLSTATE support | |
| F021 | Core | Basic information schema | |
| F021-01 | Core | COLUMNS view | |
| F021-02 | Core | TABLES view | |
| F021-03 | Core | VIEWS view | |
| F021-04 | Core | TABLE_CONSTRAINTS view | |
| F021-05 | Core | REFERENTIAL_CONSTRAINTS view | |
| F021-06 | Core | CHECK_CONSTRAINTS view | |
| F031 | Core | Basic schema manipulation | |
| F031-01 | Core | CREATE TABLE statement to create persistent base tables | |
| F031-02 | Core | CREATE VIEW statement | |
| F031-03 | Core | GRANT statement | |
| F031-04 | Core | ALTER TABLE statement: ADD COLUMN clause | |
| F031-13 | Core | DROP TABLE statement: RESTRICT clause | |
| F031-16 | Core | DROP VIEW statement: RESTRICT clause | |
| F031-19 | Core | REVOKE statement: RESTRICT clause | |
| F032 | CASCADE drop behavior | ||
| F033 | ALTER TABLE statement: DROP COLUMN clause | ||
| F034 | Extended REVOKE statement | ||
| F034-01 | REVOKE statement performed by other than the owner of a schema object | ||
| F034-02 | REVOKE statement: GRANT OPTION FOR clause | ||
| F034-03 | REVOKE statement to revoke a privilege that the grantee has WITH GRANT OPTION | ||
| F041 | Core | Basic joined table | |
| F041-01 | Core | Inner join (but not necessarily the INNER keyword) | |
| F041-02 | Core | INNER keyword | |
| F041-03 | Core | LEFT OUTER JOIN | |
| F041-04 | Core | RIGHT OUTER JOIN | |
| F041-05 | Core | Outer joins can be nested | |
| F041-07 | Core | The inner table in a left or right outer join can also be used in an inner join | |
| F041-08 | Core | All comparison operators are supported (rather than just =) | |
| F051 | Core | Basic date and time | |
| F051-01 | Core | DATE data type (including support of DATE literal) | |
| F051-02 | Core | TIME data type (including support of TIME literal) with fractional seconds precision of at least 0 | |
| F051-03 | Core | TIMESTAMP data type (including support of TIMESTAMP literal) with fractional seconds precision of at least 0 and 6 | |
| F051-04 | Core | Comparison predicate on DATE, TIME, and TIMESTAMP data types | |
| F051-05 | Core | Explicit CAST between datetime types and character types | |
| F051-06 | Core | CURRENT_DATE | |
| F051-07 | Core | LOCALTIME | |
| F051-08 | Core | LOCALTIMESTAMP | |
| F052 | Enhanced datetime facilities | Intervals and datetime arithmetic | |
| F081 | Core | UNION and EXCEPT in views | |
| F111-02 | READ COMMITTED isolation level | ||
| F131 | Core | Grouped operations | |
| F131-01 | Core | WHERE, GROUP BY, and HAVING clauses supported in queries with grouped views | |
| F131-02 | Core | Multiple tables supported in queries with grouped views | |
| F131-03 | Core | Set functions supported in queries with grouped views | |
| F131-04 | Core | Subqueries with GROUP BY and HAVING clauses and grouped views | |
| F131-05 | Core | Single row SELECT with GROUP BY and HAVING clauses and grouped views | |
| F171 | Multiple schemas per user | ||
| F191 | Enhanced integrity management | Referential delete actions | |
| F201 | Core | CAST function | |
| F221 | Core | Explicit defaults | |
| F222 | INSERT statement: DEFAULT VALUES clause | ||
| F231 | Privilege Tables | ||
| F231-01 | TABLE_PRIVILEGES view | ||
| F231-02 | COLUMN_PRIVILEGES view | ||
| F231-03 | USAGE_PRIVILEGES view | ||
| F251 | Domain support | ||
| F261 | Core | CASE expression | |
| F261-01 | Core | Simple CASE | |
| F261-02 | Core | Searched CASE | |
| F261-03 | Core | NULLIF | |
| F261-04 | Core | COALESCE | |
| F271 | Compound character literals | ||
| F281 | LIKE enhancements | ||
| F302 | OLAP facilities | INTERSECT table operator | |
| F302-01 | OLAP facilities | INTERSECT DISTINCT table operator | |
| F302-02 | OLAP facilities | INTERSECT ALL table operator | |
| F304 | OLAP facilities | EXCEPT ALL table operator | |
| F311-01 | Core | CREATE SCHEMA | |
| F311-02 | Core | CREATE TABLE for persistent base tables | |
| F311-03 | Core | CREATE VIEW | |
| F311-05 | Core | GRANT statement | |
| F321 | User authorization | ||
| F361 | Subprogram support | ||
| F381 | Extended schema manipulation | ||
| F381-01 | ALTER TABLE statement: ALTER COLUMN clause | ||
| F381-02 | ALTER TABLE statement: ADD CONSTRAINT clause | ||
| F381-03 | ALTER TABLE statement: DROP CONSTRAINT clause | ||
| F391 | Long identifiers | ||
| F401 | OLAP facilities | Extended joined table | |
| F401-01 | OLAP facilities | NATURAL JOIN | |
| F401-02 | OLAP facilities | FULL OUTER JOIN | |
| F401-03 | OLAP facilities | UNION JOIN | |
| F401-04 | OLAP facilities | CROSS JOIN | |
| F411 | Enhanced datetime facilities | Time zone specification | |
| F421 | National character | ||
| F431 | Read-only scrollable cursors | ||
| F431-01 | FETCH with explicit NEXT | ||
| F431-02 | FETCH FIRST | ||
| F431-03 | FETCH LAST | ||
| F431-04 | FETCH PRIOR | ||
| F431-05 | FETCH ABSOLUTE | ||
| F431-06 | FETCH RELATIVE | ||
| F441 | Extended set function support | ||
| F471 | Core | Scalar subquery values | |
| F481 | Core | Expanded NULL predicate | |
| F491 | Enhanced integrity management | Constraint management | |
| F501 | Core | Features and conformance views | |
| F501-01 | Core | SQL_FEATURES view | |
| F501-02 | Core | SQL_SIZING view | |
| F501-03 | Core | SQL_LANGUAGES view | |
| F502 | Enhanced documentation tables | ||
| F502-01 | SQL_SIZING_PROFILES view | ||
| F502-02 | SQL_IMPLEMENTATION_INFO view | ||
| F502-03 | SQL_PACKAGES view | ||
| F511 | BIT data type | ||
| F531 | Temporary tables | ||
| F555 | Enhanced datetime facilities | Enhanced seconds precision | |
| F561 | Full value expressions | ||
| F571 | Truth value tests | ||
| F591 | OLAP facilities | Derived tables | |
| F611 | Indicator data types | ||
| F651 | Catalog name qualifiers | ||
| F701 | Enhanced integrity management | Referential update actions | |
| F711 | ALTER domain | ||
| F761 | Session management | ||
| F771 | Connection management | ||
| F781 | Self-referencing operations | ||
| F791 | Insensitive cursors | ||
| F801 | Full set function | ||
| S071 | Enhanced object support | SQL paths in function and type name resolution | |
| S111 | Enhanced object support | ONLY in query expressions | |
| S211 | Enhanced object support, SQL/MM support | User-defined cast functions | |
| T031 | BOOLEAN data type | ||
| T141 | SIMILAR predicate | ||
| T151 | DISTINCT predicate | ||
| T171 | LIKE clause in table definition | ||
| T191 | Enhanced integrity management | Referential action RESTRICT | |
| T201 | Enhanced integrity management | Comparable data types for referential constraints | |
| T211-01 | Enhanced integrity management, Active database | Triggers activated on UPDATE, INSERT, or DELETE of one base table | |
| T211-02 | Enhanced integrity management, Active database | BEFORE triggers | |
| T211-03 | Enhanced integrity management, Active database | AFTER triggers | |
| T211-04 | Enhanced integrity management, Active database | FOR EACH ROW triggers | |
| T211-07 | Enhanced integrity management, Active database | TRIGGER privilege | |
| T212 | Enhanced integrity management | Enhanced trigger capability | |
| T231 | SENSITIVE cursors | ||
| T241 | START TRANSACTION statement | ||
| T312 | OVERLAY function | ||
| T321-01 | Core | User-defined functions with no overloading | |
| T321-03 | Core | Function invocation | |
| T321-06 | Core | ROUTINES view | |
| T321-07 | Core | PARAMETERS view | |
| T322 | PSM, SQL/MM support | Overloading of SQL-invoked functions and procedures | |
| T323 | Explicit security for external routines | ||
| T351 | Bracketed SQL comments (/*...*/ comments) | ||
| T441 | ABS and MOD functions | ||
| T501 | Enhanced EXISTS predicate | ||
| T551 | Optional key words for default syntax | ||
| T581 | Regular expression substring function | ||
| T591 | UNIQUE constraints of possibly null columns |