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 I've worked with personally, or. I anticipate to find use for in the near future.

Beta- versions of software are not examined. I'm sorry about the colors.

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. However, such. non- default configuration options are not of great value for people.

• Timestamps in MySQL generally used to track changes to records, and are often updated every time the record is changed. If you want to store a specific value you.
• While reading what other developers had done with database objects in PHP (and even Java) I noticed several characteristics which I did not have in my previous.

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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'. Bury Your Dead Beauty And The Breakdown Download Youtube. 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 structure/definition 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 .. 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 .. Instead, MSSQL has a special SELECT .. INTO copies NOT NULL column attributes, but nothing else. Documentation. Complies with the core of the feature (T1. T1. 73). 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 1< > 1. Documentation. On my TODO. The SQL- standard states that relations are unordered, but. DECLARE cursorname CURSOR FORSELECT .. WHERE .. ORDER BY column.

However, the DBMS may. ID T6. 11, . ORDER BY .. NULLS FIRSTor. .. ORDER BY .. NULLS LASTAs well as in cursor definitions, it allows ORDER BY in other contexts. 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.

ROW. This involves: DECLARE cursor- name CURSOR FOR .. OPEN cursor- name.

FETCH .. CLOSE cursor- name. Supports all standards- based approaches. 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. Doesn't support the standard.

Alternative solution. SELECT columns. FROM tablename. ORDER BY key ASCLIMIT n. Documentation. Supports ROW. You may want to experiment with this.

Ask Tom has an article on ROWNUM. Supports neither ROW. Thus, the query may return more than n.

Some call this a quota- query. The following examples are based on this table: SELECT * FROM person ORDER BY age ASC. If the DBMS supports elementary OLAP (feature ID F6.

RANK() OVER. SELECT * FROM (SELECTRANK() OVER (ORDER BY age ASC) AS ranking,person. Scalar subqueries.

In practice, a Postgre. SQL- only method was used instead, in order to obtain. SELECT *FROM person.

WHERE (age < = (SELECT age FROM person. ORDER BY age ASCLIMIT 1 OFFSET 2       - - 2=n- 1)) IS NOT FALSE(Change < = to > = and ASC to DESC in the positions marked like this in order to get a top- 3 oldest query instead.)Documentation. Supports the fast standard SQL variant. In practice, a MSSQL- only expression had to be used instead, in order to obtain acceptable query performance.

SELECT TOP 3 WITH TIES *FROM person. ORDER BY age ASC(Change ASC to DESC in the position marked like this in order to get a top- 3 oldest query instead.)Documentation. Supports the slow standard SQL. In practice, this My. SQL- specific solution should be used instead. SELECT *. FROM person. WHERE age < = COALESCE( - - note: no space between .

If you want the opposite, then change. ASC- > DESC and DESC- > ASC. By the way, Use the Index, Luke! This involves: DECLARE cursor- name CURSOR FOR .. OPEN cursor- name. FETCH RELATIVE number- of- rows- to- skip .. CLOSE cursor- name.

Supports all the standards- based approaches. Instead, see if the DB2 driver for your programming environment supports SQLFetch. Scroll(). Documentation: OLAP functions, the FETCH statement. Alternative solution. SELECT columns. FROM tablename.

ORDER BY key. ASCLIMIT n OFFSET skip. In older versions of My.

SQL, the LIMIT- syntax is less clear. I'm unsure if Oracle's cursor support is standards- compliant. An other reason for the re- write is that ROWNUM is a reserved word in Oracle, with special meaning. The Oracle code becomes. SELECT * FROM (SELECTROW.

You may want to experiment with this. Ask Tom has an article on ROWNUM. Supports neither OFFSET.. FETCH FIRST nor ROW. Supports cursors.

In this case, be careful not. Consider the following example (where Postgre. SQL is used): SELECT * FROM person ORDER BY age ASC.

The result set is fetched in two queries where. DBMS happens to sort differently, as above.

If you want to guard against this, too, then you should see if use of an insensitive cursor is an option in your application. Use of cursors to paginate result sets usually require that your application is stateful, which is not the case in many web- application settings. Alternatively, you could let the application cache the complete result set (e. One handy use. of row value constructors is when inserting several rows at a time, such as. INSERT INTO tablename.

VALUES (0,'foo') , (1,'bar') , (2,'baz'); — which may be read as a shorthand for. INSERT INTO tablename VALUES (0,'foo'); INSERT INTO tablename VALUES (1,'bar'); INSERT INTO tablename VALUES (2,'baz'); Supported.(since version 8. Supported. Supported.(since version 2.

Supported. An Oracle- specific kludge. INSERT INTO tablename. SELECT 0,'foo' FROM DUALUNION ALLSELECT 1,'bar' FROM DUALUNION ALLSELECT 2,'baz' FROM DUALAlternatively: INSERT ALLINTO tablename VALUES(0,'foo')INTO tablename VALUES(1,'bar')INTO tablename VALUES(2,'baz')SELECT null FROM dual.

On my TODO. The BOOLEAN type is optional (has feature ID T0. However, it seems that endless discussions of how.

NULL is to be interpreted for a boolean value is holding BOOLEAN from becoming. It is. unclear from the specification if the DBMS must support. UNKNOWN, NULL or both as boolean literals.

In this author's. UNKNOWN literal. in order to simplify the situation and let the normal SQL. It's defined that TRUE > FALSE (true larger than false). Follows the standard. If you insert an integer. BIT, then. the inserted value will silently be converted to 1. Rudy Limeback has some notes about oddities with the MSSQL BIT type.

Documentation. Offers a non- conforming BOOLEAN type. My. SQL's BOOLEAN. TINYINT(1) type. However. To check if. the database- value was really NULL, use was. Null(). For the following section, I have used this test- SQL to. SQL. as simple as this has to be adjusted for some products): Test steps: CREATE TABLE chartest (charval.