Comparison of different SQL implementations. The goal of this page which is a work in progress is to gather information relevant for people who are porting SQL from. SQL. The following tables compare how different. DBMS products handle various SQL and related features. If possible, the tables also. SQL. standard. I will only write about subjects that Ive worked with personally, or. ANYAqHe6VJ.jpg' alt='How To Show Serial Number In Sql Query To Find' title='How To Show Serial Number In Sql Query To Find' />Learn PostgreSQL quickly through a practical PostgreSQL tutorial designed for database administrators and application developers. Note The demos on this page are intended to show valid syntax but it is far easier to use a hint to make a mess of things than it is to improve things. Using parallel processing only makes sense for your customers in specific situations. Find out when to use parallel SQL with the Oracle databse to avoid excessive usage. I anticipate to find use for in the near future. Snes Emulator 64 Bit Windows 8 on this page. Subjects on which there are no significant implementation variances are not. Beta versions of software are not examined. Im sorry about the colors. That is, even without the RECOMPILE hint, SQL Server is able to avoid the access to Suppliers. If you look in the execution plan, you find a Filter operator above the. The output of this query looks like SQL Systimemodelint10g. Statistic Name Time s Percent of Total DB Time. Comparison of different SQL implementations. The goal of this page which is a work in progress is to gather information relevant for people who are porting. They are a result of wanting to mark each DBMS. If you have corrections or suggestions, please. The following SQL standard and implementations have been. This is important for My. SQL and MSSQL Their interpretation of SQL. My. SQL, there is a dedicated documentation page about this. However, such. non default configuration options are not of great value for people. SQL applications because the developer often cannot rely on non default. Views are part of the standard, and they may be updated, as long as it makes sense. SQL 2. 00. 8 has a rather complicated set of rules governing when a view is updatable, basically saying that a view is updatable, as long as the update operation translates into an unambiguous change. SQL 9. 2 was more restrictive, specifying that updatable views cannot be derived from more than one base table. Has views. Breaks that standard by not allowing updates to views offers the non standard rules system as a work around. Conforms to at least SQL 9. Conforms to at least SQL 9. Conforms to at least SQL 9. Conforms to at least SQL 9. Conforms to at least SQL 9. All the DBMSes support basic INNER JOINs, but vary in their support for other join types. In the following feature chart, a. Remarks Note that FULL joins may be emulated with a union of a left and a right join. Objective An existing table, t. I. e., only the structuredefinition of the table is copied. Optional feature T1. LIKE clause in table definition. CREATE TABLE t. 2 LIKE t. The DBMS may support an extension of this feature T1. CREATE TABLE t. 2 LIKE t. INCLUDING IDENTITY INCLUDING DEFAULTS INCLUDING GENERATED If INCLUDING DEFAULTS is not specified, column defaults will not be part of t. IDENTITY and GENERATED properties. Triggers, CHECK constraints, and other non trivial table features are not copied to the new table. Complies with the core of the feature T1. The extended T1. 73 feature is only partially supported, and extended with a few non standard options. The INCLUDING IDENTITY and INCLUDING GENERATED options are not supported. INCLUDING CONSTRAINTS and INCLUDING INDEXES options are added. Postgre. SQL does not allow you to copy the structure of a view, using CREATE TABLE. LIKE. For that, you may use another construct CREATE TABLE copytable AS SELECT FROM viewname WHERE false. Documentation. Behaves as if inspired by the standard. I. e., DB2 conforms to the standard, except. LIKE. clause is stated outside any parenthesisthe extended INCLUDING GENERATED option is not supported. DB2 defaults to copy IDENTITY, DEFAULTS, and GENERATED properties, unless EXCLUDING IDENTITY andor EXCLUDING DEFAULTS is specified. Example. CREATE TABLE t. LIKE t. 1 INCLUDING DEFAULTSDB2 allows you to copy the structure of a view into a table. Documentation. Does not support the standard. Instead, MSSQL has a special SELECT. INTO. FROM. construct which can be combined with an impossible WHERE clause to copy structure only. SELECT INTO t. 2 FROM t. WHERE 1lt 1. The source t. SELECT. INTO copies NOT NULL column attributes, but nothing else. Documentation. Complies with the core of the feature T1. T1. 73. My. SQL does not allow you to copy the structure of a view into a table. Documentation. Does not support the standard. Oracle lets you copy a table structure using a special CREATE TABLE. AS construct, combined with an impossible WHERE clause. CREATE TABLE t. 2 AS SELECT FROM t. WHERE 1lt 1. Documentation. On my TODO. The SQL standard states that relations are unordered, but. DECLARE cursorname CURSOR FORSELECT. FROM. WHERE. ORDER BY columnname. The DBMS may additionally allow ORDER BY outside cursor definitions optional feature IDs F8. F8. 51, F8. 52, F8. Since SQL 2. 00. NULLs should be ordered in comparison with. NULL values, except that any two NULLs are to be considered equally ordered, and. NULLs should sort either above or below all non NULL values. However, the DBMS may. ID T6. 11, Elementary OLAP operations. NULLs should sort first or last. ORDER BY. NULLS FIRSTor. ORDER BY. NULLS LASTAs well as in cursor definitions, it allows ORDER BY in other contexts. By default, NULLs are considered higher than any non NULL value however,since version 8. NULLS FIRST or NULLS LAST to the ORDER BY expression. DOCUMENTATIONAs well as in cursor definitions, it allows ORDER BY in other contexts. NULLs are considered higher than any non NULL value. DOCUMENTATIONAs well as in cursor definitions, it allows ORDER BY in other contexts. NULLs are considered lower than any non NULL value. DOCUMENTATIONAs well as in cursor definitions, it allows ORDER BY in other contexts. NULLs are considered lower than any non NULL value. ASC is changed to DESC, or DESC to ASC this minus before column name. Documentation. As well as in cursor definitions, it allows ORDER BY in other contexts. By default, NULLs are considered higher. NULL value however, this sorting behaviour may be changed. NULLS FIRST or NULLS LAST. ORDER BY expression. Beware of Oracles strange treatment of empty strings and NULLs as. DOCUMENTATIONAs well as in cursor definitions, it allows ORDER BY in other contexts. NULLs are considered lower than any non NULL value. DOCUMENTATIONObjective Want to only get n rows in the result set. Usually only makes sense in connection with an ORDER BY expression. Note This is not the same as a top n query see next section. Note also Some of the queries below may not be legal in all situations, such as in views or sub queries. By the way, Use The Index, Luke The SQL standard provides three ways of performing a simple limit. Using FETCH FIRST since SQL 2. Non core feature IDs F8. F8. 57, F8. 58, and F8. SELECT. FROM. WHERE. ORDER BY. FETCH FIRST n ROWS ONLYYou may write ROW instead of ROWS. Using a Window function since SQL 2. Non core Feature ID T6. ROWNUMBER OVER. SELECT FROM SELECTROWNUMBER OVER ORDER BY key ASC AS rownumber,columns. FROM tablename AS foo. WHERE rownumber lt  n. Using a cursor. If your application is stateful in contrast to web applications which. ID E1. 21 instead. This involves DECLARE cursor name CURSOR FOR. OPEN cursor name. FETCH. CLOSE cursor name. Supports all standards based approaches. In old Postgre. SQL versions versions 8. Postgre. SQL and My. SQL specific method was used. SELECT columns. FROM tablename. ORDER BY key ASCLIMIT n. Note that LIMITchanges the semantics of SELECT. FOR UPDATE. Documentation Supports all standards based approaches. Documentation OLAP functions. FETCH FIRST general page about the SELECT statement use your browsers search function to locate FETCH FIRST. Supports the ROWNUMBERsince MSSQL 2. FETCH FIRST. MSSQL 2. ROWNUMBER. Instead, a MSSQL 2. SELECT TOP ncolumns. FROM tablename. ORDER BY key ASC. The TOP construct is still available in MSSQL 2. SQL work. Documentation. Doesnt support the standard.