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Null, NoneManual ChaptersPG1844.2.2. Null, None If an SQL null value is passed to a function, the argument value will appear as None in Python. For example, the function definition of pymax shown in Section 44.1 will re…Null, None NULLIFSQL CommandsPG189.18.3. NULLIF # NULLIF(value1, value2) The NULLIF function returns a null value if value1 equals value2; otherwise it returns value1. This can be used to perform the inverse operation of th…Conditional Expressions › NULLIF NULLIFManual ChaptersPG189.18.3. NULLIF NULLIF(value1, value2) The NULLIF function returns a null value if value1 equals value2; otherwise it returns value1. This can be used to perform the inverse operation of the …NULLIF NULLIFFunctionsReferenceNULLIF Conditional Expressions 10 The NULLIF function returns a null value if value1 equals value2; otherwise it returns value1. This can be used to perform the inverse operation of the COAL…Functions · Conditional Expressions num_nonnullsFunctionsReferencenum_nonnulls Comparison Functions And Operators 10 returns the number of non-null arguments num_nonnulls ( VARIADIC "any" ) returns the number of non-null arguments 11 12 13 Returns the numb…Functions · Comparison Functions And Operators num_nullsFunctionsReferencenum_nulls Comparison Functions And Operators 10 returns the number of null arguments num_nulls ( VARIADIC "any" ) returns the number of null arguments 11 12 13 Returns the number of null arg…Functions · Comparison Functions And Operators num_os_semaphoresConfigurationReferencenum_os_semaphores Preset Options 18 Reports the number of semaphores that are needed for the server based on the configured number of allowed connections (max_connections), allowed autovacuu…Configuration · Preset Options numberExtensionsExtensionsVariable-width integer data type for PostgreSQL datatype integer postgresql-number Data typesData types · Extensions numeralExtensionsExtensionsnumeral datatypes extension numeral Data typesData types · Extensions numericData TypesPG18numeric [ (p, s) ] decimal [ (p, s) ] exact numeric of selectable precisionData Types Numeric ConstantsManual ChaptersPG184.1.2.6. Numeric Constants Numeric constants are accepted in these general forms: digits digits.[digits][e[+-]digits] [digits].digits[e[+-]digits] digitse[+-]digits where digits is one or mo…Numeric Constants Numeric TypesManual ChaptersPG188.1. Numeric Types Numeric types consist of two-, four-, and eight-byte integers, four- and eight-byte floating-point numbers, and selectable-precision decimals. Table 8.2 lists the availabl…Numeric Types numeric, decimalManual ChaptersPG1834.4.4.2.3. numeric, decimal The handling of the numeric and decimal types is similar to the interval type: It requires defining a pointer, allocating some memory space on the heap, and acce…numeric, decimal numeric_domainsExtensionsExtensionsCustom numeric domains for PostgreSQL domain latitude-longitude numeric validation numeric_domains Data typesData types · Extensions numhstoreExtensionsExtensionsAdds inthstore and floathstore numeric hstore types and helpers pg_numhstore Data typesData types · Extensions nummultirangeData TypesPG18numrange — Range of numeric, nummultirange — corresponding MultirangeRange Types › Built-in Range and Multirange Types numnodeFunctionsReferencenumnode Text Search Functions And Operators 10 number of lexemes plus operators in tsquery numnode ( tsquery ) → integer number of lexemes plus operators in tsquery 11 12 13 Returns the numb…Functions · Text Search Functions And Operators numpgsqlExtensionsExtensionsArray and numerical computing library for PostgreSQL array math numeric random statistics numpgsql Functions and aggregatesFunctions and aggregates · Extensions numpy_plpython2uExtensionsExtensionstransform between numpy and plpython2u numpy-arrays plpython postgresql-extension numpy_plpython2u Procedural languagesProcedural languages · Extensions numpy_plpython3uExtensionsExtensionstransform between numpy and plpython3u numpy-arrays plpython postgresql-extension numpy_plpython3u Procedural languagesProcedural languages · Extensions numpy_plpythonuExtensionsExtensionstransform between numpy and plpythonu numpy-arrays plpython postgresql-extension numpy_plpythonu Procedural languagesProcedural languages · Extensions numrangeData TypesPG18numrange — Range of numeric, nummultirange — corresponding MultirangeRange Types › Built-in Range and Multirange Types nvlfuncExtensionsExtensionsOracle-compatible NVL function compatibility oracle nvlfunc CompatibilityCompatibility · Extensions oai_fdwExtensionsExtensionsOAI-PMH foreign data wrapper for PostgreSQL fdw metadata oai-pmh oai_fdw Foreign data wrappersForeign data wrappers · Extensions OAuth Authorization/AuthenticationManual ChaptersPG1820.15. OAuth Authorization/Authentication OAuth 2.0 is an industry-standard framework, defined in RFC 6749, to enable third-party applications to obtain limited access to a protected resourc…OAuth Authorization/Authentication OAuth SupportManual ChaptersPG1832.20. OAuth Support libpq implements support for the OAuth v2 Device Authorization client flow, documented in RFC 8628, as an optional module. See the installation documentation for informa…OAuth Support OAuth Validator CallbacksManual ChaptersPG1850.3. OAuth Validator Callbacks OAuth validator modules implement their functionality by defining a set of callbacks. The server will call them as required to process the authentication requ…OAuth Validator Callbacks OAuth Validator ModulesManual ChaptersPG18Chapter 50. OAuth Validator Modules PostgreSQL provides infrastructure for creating custom modules to perform server-side validation of OAuth bearer tokens. Because OAuth implementations var…OAuth Validator Modules oauth_client_idCommand-line ToolsPG18oauth_client_id An OAuth 2.0 client identifier, as issued by the authorization server. If the PostgreSQL server requests an OAuth token for the connection (and if no custom OAuth hook is ins…Database Connection Control Functions › Parameter Key Words oauth_client_secretCommand-line ToolsPG18oauth_client_secret The client password, if any, to use when contacting the OAuth authorization server. Whether this parameter is required or not is determined by the OAuth provider; "public…Database Connection Control Functions › Parameter Key Words oauth_issuerCommand-line ToolsPG18oauth_issuer The HTTPS URL of a trusted issuer to contact if the server requests an OAuth token for the connection. This parameter is required for all OAuth connections; it should exactly ma…Database Connection Control Functions › Parameter Key Words oauth_scopeCommand-line ToolsPG18oauth_scope The scope of the access request sent to the authorization server, specified as a (possibly empty) space-separated list of OAuth scope identifiers. This parameter is optional and …Database Connection Control Functions › Parameter Key Words oauth_validator_librariesConfigurationReferenceoauth_validator_libraries Connections and Authentication 18 The library/libraries to use for validating OAuth connection tokens. If only one validator library is provided, it will be used by…Configuration · Connections and Authentication OAUTHBEARER AuthenticationManual ChaptersPG1854.3.2. OAUTHBEARER Authentication OAUTHBEARER is a token-based mechanism for federated authentication. It is described in detail in RFC 7628. A typical exchange differs depending on whether…OAUTHBEARER Authentication obj_descriptionFunctionsReferenceobj_description System Information Functions And Operators 10 get comment for a database object obj_description ( object_oid, catalog_name ) → text get comment for a database object obj_desc…Functions · System Information Functions And Operators objectWait EventsReferenceobject Lock 10 Waiting to acquire a lock on a non-relation database object. 11 12 13 14 15 16 17 18 19 20 9.6 Sub-second handoff during ordinary writes or planned DDL can be normal. Investig…Wait Events · Lock Object Identifier TypesManual ChaptersPG188.19. Object Identifier Types Object identifiers (OIDs) are used internally by PostgreSQL as primary keys for various system tables. Type oid represents an object identifier. There are also …Object Identifier Types Object Information and Addressing FunctionsManual ChaptersPG189.27.5. Object Information and Addressing Functions Table 9.81 lists functions related to database object identification and addressing. Table 9.81. Object Information and Addressing Functio…Object Information and Addressing Functions Object Name OptionsManual ChaptersPG18F.38.1.2. Object Name Options These options can be used to control the names used in SQL statements sent to the remote PostgreSQL server. These options are needed when a foreign table is cre…Object Name Options object_referenceExtensionsExtensionsProvides immutable references to Postgres objects. object_reference FeaturesFeatures · Extensions