1. What is New for T-SQL in SQL Server 2012 & SQL Azure
Tobias Ternström
Senior Program Manager Lead, SQL Engine

2. Our organization SQL Server RDBMS Team Applications and Components
External Apps
Excel
Project
Server
Content
Management
Server
MOM
MS CRM
Outlook
Visual Studio
Dynamics
LCS
Commerce
Server
Oslo
Exchange
Biztalk Server
Sharepoint
DPM
SQL Replication
SQL Management
Tools
SQL Reporting
Services
SQL Analysis
Services
SQL Integration
Services
SQL Server RDBMS Team
Connectivity
MDAC
ODBC, OLE-DB
SNAC
ODBC, OLE-DB
EDM
Ado.Net
SQL Client
JDBC
App Platform T-SQL Language, Data-Tier Application Model, Types, Libraries
SQL Engine
Query Processor Query Opimization & Execution
Storage & Admin Storage Engine, DR etc.
High Availability Mirroring, Clustering, etc.

3. Overview New Query & Schema Constructs Improved Error Handling
Additional Scalar Functions
Robust Metadata Discovery
Improvements to Dynamic SQL

4. Simplified Paging & UTF-16
Support for Simplified Paging
SELECT ORDER BY ... OFFSET <expr> ROWS FETCH NEXT <expr> ROWS ONLY
Support for UTF-16, introducing _SC collations
Common Unicode characters occupy 16-bits each (NCHAR / NVARCHAR)
Rarer Unicode characters occupy 2 x 16-bits each
“Supplementary Characters”, “Surrogate Pairs”
Ancient scripts; Music Notation; Math Symbols etc.
Available in SQL Azure Now!

5. Sequence Generators
New Database Object, similar to the IDENTITY property
Separates number-generation from column and table
ANSI standard compliant implementation
CREATE SEQUENCE MySchema.IdSequence AS INT START WITH INCREMENT BY 1; GO INSERT INTO Employees (EmployeeId, Name)
VALUES (NEXT VALUE FOR MySchema.IdSequence, 'Jane');
INSERT INTO Contractors (ContractorId, Name)
VALUES (NEXT VALUE FOR MySchema.IdSequence, 'John');

6. Sequence Generators CREATE SEQUENCE [ schema_name . ] sequence_name
[ AS { <built_in_integer_type> | <user-defined_integer_type> } ]
[ START WITH <constant> ]
[ INCREMENT BY <constant> ]
[ MINVALUE <constant> | NO MINVALUE ]
[ MAXVALUE <constant> | NO MAXVALUE ]
[ CYCLE | NO CYCLE ]
[ CACHE [<constant> ] | NO CACHE ]

7. Sequence Generators Generates a Predictable number of values
SELECT
NEXT VALUE FOR MySequence ,….
FROM MyTable;
Generates a Predictable number of values
Achieved by restricting where NEXT VALUE FOR can be used
Supported in DEFAULT-constraints
Semantically correct support for generating values based on an order (extension to ANSI) SELECT NEXT VALUE FOR MySeq OVER (ORDER BY OrderDate ASC) AS OrderId ,OrderDate ,CustomerId FROM Orders;
Generate a range using sp_sequence_get_range

8. Extended support for Window Functions
SQL:2008 Compliant Functionality
Windowed Aggregates
OVER (<partition_clause> <order_clause> <frame_clause> )
New Ranking Functions
CUME_DIST, PERCENT_RANK
Inverse Distribution Functions
PERCENTILE_CONT, PERCENTILE_DISC
LAG / LEAD Functions
FIRST_VALUE / LAST_VALUE Functions

9. Extended support for Window Functions
<partition_clause>
<order_clause>
Full support for ordering
<frame_clause>
Full support for ROWS
RANGE supports well-known bounds only
Supported Aggregates
COUNT , COUNT_BIG, SUM, AVG, MIN, MAX
STDEV, STDEVP, VAR, VARP, CHECKSUM_AGG

10. Extended support for Window Functions
RANGE/ROWS units
ROWS | RANGE BETWEEN <B1> AND <B2>
ROWS | RANGE <B1>
B1 and B2 can be any of
UNBOUNDED PRECEDING
UNBOUNDED FOLLOWING
CURRENT ROW
For ROWS only
<scalar expression> PRECEDING
<scalar expression> FOLLOWING
For short form FOLLOWING cannot be used
Notes
B1 must be less or equal to B2, otherwise NULL is returned (except for COUNT)
New conditional keywords: UNBOUNDED, PRECEDING, FOLLOWING, ROWS, RANGE, CURRENT ROW
Short form with left border only (right border is current row)
Full form with left and right border
ROWS BETWEEN 10 PRECEDING AND 5 PRECEDING is OK

11. <frame_clause>
Supported framing options
ROWS UNBOUNDED PRECEDING
ROWS <unsigned integer literal> PRECEDING
ROWS CURRENT ROW
ROWS BETWEEN UNBOUNDED PRECEDING AND <unsigned integer literal> PRECEDING
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
ROWS BETWEEN UNBOUNDED PRECEDING AND <unsigned integer literal> FOLLOWING
ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
ROWS BETWEEN <unsigned integer literal> PRECEDING AND <unsigned integer literal> PRECEDING
ROWS BETWEEN <unsigned integer literal> PRECEDING AND CURRENT ROW
ROWS BETWEEN <unsigned integer literal> PRECEDING AND <unsigned integer literal> FOLLOWING
ROWS BETWEEN <unsigned integer literal> PRECEDING AND UNBOUNDED FOLLOWING
ROWS BETWEEN CURRENT ROW AND CURRENT ROW
ROWS BETWEEN CURRENT ROW AND <unsigned integer> FOLLOWING
ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
ROWS BETWEEN <unsigned integer literal> FOLLOWING AND <unsigned integer> FOLLOWING
ROWS BETWEEN <unsigned integer literal> FOLLOWING AND UNBOUNDED FOLLOWING
RANGE UNBOUNDED PRECEDING
RANGE CURRENT ROW
RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
RANGE BETWEEN CURRENT ROW AND CURRENT ROW

12. SQL Server Code-named Denali
New Query & Schema Constructs
Improved Error Handling
Additional Scalar Functions
Robust Metadata Discovery
Improvements to Dynamic SQL

13. The Error Handling Quiz
What is returned to the client? a) Error b) Error & Hello
RAISERROR(‘Error‘, 10, 1); PRINT ‘Hello‘;
RAISERROR(‘Error‘, 16, 1); PRINT ‘Hello‘;
RAISERROR(‘Error‘, 20, 1); PRINT ‘Hello‘;
RAISERROR(‘Error‘, 20, 1) WITH LOG; PRINT ‘Hello‘;
CREATE PROC sp1 AS RAISERROR(‘Error‘, 11, 1); PRINT ‘Hello‘;
CREATE PROC sp2 AS RAISERROR(‘Error‘, 10, 1); PRINT ‘Hello‘;
EXEC sp1;
EXEC sp2;
BEGIN TRY EXEC sp1; END TRY BEGIN CATCH END CATCH
BEGIN TRY EXEC sp2; END TRY BEGIN CATCH END CATCH

14. Available in SQL Azure Now!
What is in Denali?
Introducing THROW which…
always THROWs
is even spelled correctly!
Syntax
THROW <number>, <message>, <state>;
Batch aborts if not in SET XACT_ABORT ON where it Transaction-aborts
Does not automatically use sys.messages
re-THROW
BEGIN CATCH …; THROW; END CATCH
Available in SQL Azure Now!

15. SQL Server Code-named Denali
New Query & Schema Constructs
Improved Error Handling
Additional Scalar Functions
Robust Metadata Discovery
Improvements to Dynamic SQL

16. Additional Scalar Functions
Available in SQL Azure’s Next SR
New conversion functions for all types:
TRY_CONVERT(data_type[(length)], [,style])
TRY_CAST(expression AS data_type[(length)])
New conversion functions to and from strings:
FORMAT(value, format [,culture])
PARSE(string_value AS data_type [USING culture])
TRY_PARSE(string_value AS data_type [,USING culture])
Other functions:
IIF(boolean expr, true_value, false_value)
CHOOSE(index,val1,val2 [,valN])
CONCAT(val1, val2…[,valn])

17. Additional Scalar Functions
Available in SQL Azure’s Next SR
New date & time related functions:
EOMONTH(date [, months_to_add])
DATEFROMPARTS(year, month, day)
TIMEFROMPARTS(hour, minutes, seconds, fractions, scale)
DATETIME2FROMPARTS(year, month, day ,hour, minutes, seconds, fractions, scale)
DATETIMEFROMPARTS(year, month, day, hour, minutes, seconds, milliseconds)
SMALLDATETIMEFROMPARTS(year, month, day, hour, minutes)

18. SQL Server Code-named Denali
New Query & Schema Constructs
Improved Error Handling
Additional Scalar Functions
Robust Metadata Discovery
Improvements to Dynamic SQL

19. Robust Result set Metadata Discovery or Finally replacing SET FMTONLY ON
SET FMTONLY ON; IF(…) SELECT a FROM t1; ELSE SELECT b FROM t2; SET FMTONLY OFF;
EXEC = N' IF(…) SELECT a FROM t1; ELSE SELECT b FROM t2; ';
What is the big difference?

20. Robust Result set Metadata Discovery
Pre-Denali option is to use SET FMTONLY ON
which is sadly broken...
What will this batch return using FMTONLY?
IF (...) SELECT a, b FROM t1; ELSE SELECT c, d, e FROM t2;

21. Robust Result set Metadata Discovery
SET FMTONLY is replaced by ...
Result set metadata discovery
sp_describe_first_result_set
dm_exec_describe_first_result_set
dm_exec_describe_first_result_set_for_object
Parameter metadata discovery
sp_describe_undeclared_parameters
Jedi mind trick!
Available in SQL Azure Now!

22. Robust Metadata Discovery for Result sets – The Guranatee
The semantics of sp_describe_first_result_set provide a guarantee that if the procedure returns the first result-set metadata for some batch B, and that batch is subsequently executed with no relevant schema changes on the server, other than creating a temporary table or table variable in the batch B, between the time sp_describe_first_result_set is called and the time the result set is returned during execution (including schema changes made by the batch B), then either the batch raises an optimization-time or run-time error, the batch returns no result-set or the first result-set returned by the batch will have the same metadata that sp_describe_first_result_set described (the name, nullability and data type can differ as described under section “d” above). In case sp_describe_first_result_set returnes an empty result-set, the guarantee is that the execution of the batch will return no result-sets.

23. … simplified
sp_describe_first_result_set analyzes batch B and returns result set metadata M.
When batch B is executed,
a result set with metadata M is returned,
no result set is returned, or
an error is returned.

24. Examples a{int}, b{int} a{int}, b{int} a{int} a{nvarchar(50)}
Batch
FMTONLY
Metadata Discovery
IF(…) SELECT a{int}, b{int}FROM t1; ELSE SELECT d{int} AS a, e{int} AS b FROM t2; SELECT a{nvarchar(max)} FROM t3;
a{int}, b{int}
a{int}, b{int}
IF(…) SELECT a{int} FROM t1; ELSE SELECT d{int} + g{smallint} FROM t2;
a{int}
<none>{int}
IF(…) SELECT a{nvarchar(50)} FROM t1; ELSE SELECT a{nvarchar(120)} FROM t2;
a{nvarchar(50)}
a{nvarchar (120)}
IF(…) SELECT a{int}, b{int} FROM t1; ELSE SELECT a{varchar(50)}, b{int} FROM t2;
ERROR: Type mismatch

25. SQL Server Code-named Denali
New Query & Schema Constructs
Improved Error Handling
Additional Scalar Functions
Robust Result set Metadata Discovery
Improvements to Dynamic SQL

26. Improvements to Dynamic SQL
Support for defining a contract for returned result set(s)
EXECUTE <proc|clr proc|remote proc|function> [WITH <execute_option>[,...n ]]
{ RESULT SETS {UNDEFINED|NONE |(<result_sets_definition>)} }
 <result_sets_definition> ::= { <result_set_definition> |AS OBJECT [<object_location>.]{table_name| view_name | tvf} |AS TYPE [schema_name.]table_type_name |AS FOR XML | (…) [,...n ]}
Available in SQL Azure Now!
WITH RESULT SETS ( (ObjectID BIGINT, Name NVARCHAR(100))
); WITH RESULT SETS (AS OBJECT Sales.OrdersView); WITH RESULT SETS NONE;

27. Enforcing the contract
Batch
Metadata Discovery
Runtime
EXEC('SELECT a{int} FROM t1') WITH RESULT SETS ((b INT));
b{int}
EXEC('SELECT a{tinyint} FROM t1') WITH RESULT SETS ((b INT));
EXEC('SELECT a{datetime2} FROM t1') WITH RESULT SETS ((b INT));
ERROR: Msg 206, Operand type clash…
EXEC('SELECT a{int}, b{int} FROM t1') WITH RESULT SETS ((b INT));
ERROR: Number of columns mismatch

28. For attending this session and PASS SQLRally Nordic 2011, Stockholm
THANK YOU!
For attending this session and PASS SQLRally Nordic 2011, Stockholm