SQL Programming by George Hernandez

SQL statements can include programming elements just like most other programming languages. (You may want to see my section on Programming.)

Developer Comments. Started by two dashes -- or enclosed by slash-asterisk /* and asterisk-slash */. MySQL uses -- (note the following space), /**/ and # (the latter is just like -- ).
Statement Layout. Some specific to SQL-Transact.
- Expressions. In SQL, an expression evaluates a single data value for each row in the result set. EG: SELECT ID, 1+2, price*2 FROM TableA. In most programming languages, expressions are symbols and operators that evaluate to a single data value. Expressions can include constants, functions that return one value, column references, or variables.
Data Types. Each column, local variable, expression, and parameter has a related data type.
Identifiers. Labels for database objects.
Operators. Here is the precedence list in SQL Server:
- Unary operators: + (Positive), - (Negative), ~ (Bitwise NOT)
- Math and string operators:
  - * (Multiply), / (Division), % (Modulo)
  - + (Add), (+ Concatenate), - (Subtract)
- Comparison operators: =, >, <, >=, <=, <>, !=, !>, !<
- Bitwise operators: ^ (Bitwise XOR), & (Bitwise AND), | (Bitwise OR)
- Logical operators:
  - NOT
  - AND
  - ALL, ANY, BETWEEN, EXISTS, IN, LIKE, OR, SOME
- Assignment operator: =
Flow Control
Functions
Input/Output
Program Halts
Reserved Keywords. Certain keywords are reserved by SQL Server because they have particular use in T-SQL syntax.

There are four ways that multiple statements can be executed:

Batches are non-compiled multiple statements sent to the server. (The end of a batch is signaled in SQL Server Query Analyzer, osql, and isql by use of the GO command.)
Scripts are statements stored as files. Scripts usually consist of batches.
Stored Procedures are pre-compiled statements on the server that can be called upon.
Triggers are stored procedures that are not called but execute when certain events occur.

Page Modified: (Hand noted: 2007-10-12 21:25:46Z) (Auto noted: 2010-12-24 22:50:46Z)