The basics of MS SQL (Microsoft SQL Server) & their datatype

The basics of SQL:
What are the difference between DDL, DML and DCL commands?

1. DDL is Data Definition Language statements. 
• CREATE - to create objects in the database 
• ALTER - alters the structure of the database 
• DROP - delete objects from the database
• TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed 
• COMMENT - add comments to the data dictionary 
• GRANT - gives user's access privileges to database 
• REVOKE - withdraw access privileges given with the GRANT command
2. DML is Data Manipulation Language statements. 
• SELECT - retrieve data from the a database 
• INSERT - insert data into a table 
• UPDATE - updates existing data within a table 
• DELETE - deletes all records from a table, the space for the records remain 
• CALL - call a PL/SQL or Java subprogram 
• EXPLAIN PLAN - explain access path to data 
• LOCK TABLE - control concurrency
3. DCL is Data Control Language statements.
• COMMIT - save work done 
• SAVEPOINT - identify a point in a transaction to which you can later roll back 
• ROLLBACK - restore database to original since the last COMMIT
• SET TRANSACTION - Change transaction options like what rollback segment to use

SQL Data Type

1. Exact numerics
• bigint 
• numeric
• bit
• smallint
• decimal
• smallmoney
• int
• tinyint
• money
2. Approximate numerics
• float
• real
3. Date and time
• date
• datetimeoffset
• datetime2
• smalldatetime
• datetime
• time
4. Character strings
• char
• varchar
• text
5. Unicode character strings
• nchar
• nvarchar
• ntext
6. Binary strings
• binary
• varbinary
• image
7. Other data types
• cursor
• rowversion
• hierarchyid
• uniqueidentifier
• sql_variant
• xml
• Spatial Geometry Types
• Spatial Geography Types
• table