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IFS180.81 Intro to Data Management Chapter 5 Getting More Than Simple Columns.

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Presentation on theme: "IFS180.81 Intro to Data Management Chapter 5 Getting More Than Simple Columns."— Presentation transcript:

1 IFS180.81 Intro to Data Management Chapter 5 Getting More Than Simple Columns

2 Select Statement – Revisited General format of SELECT statement (IE. Major clauses) Two required Major clauses Required punctuation Define a duplicate row and how do we eliminate a duplicate row How is column sequencing accomplished

3 Data Types / Literals– Reviewed What is a literal Examples of Character and Numeric literal Character require single quotes, numeric does not Data Types Character Numeric Date

4 Expression / Function Building Character Mathematical Date / Time Arithmetic

5 Character Expressions and Functions Concatenation – Joining character columns / literals together Note: SQL = ||, Access = &, Oracle = CONCAT Substring function Length Function Count Function  Not strictly numeric In String function Left Pad Function

6 Character and Numeric Operations CAST function Used to convert a column reference or literal into a specified data type Why? Notice that Access does not require (as indicated by your authors). However, it is dependant on the DBMS being used.

7 Mathematical Expressions / Functions Order of Precedence: Multiplication (*) and Division (/) Addition (+) and Subtraction (-) Left to Right evaluation Parentheses (…) to control evaluation

8 Number Functions Round – Round value to specified value Round(79.5112,0)  80 Trunc – Truncate value to specified decimal Trunc(79.5112,0)  79 Mod – Returns the remainder of division Mod(1600/300)  100

9 Data and Time Arithmetic Additional and Subtraction only Use only DATE or Non-decimal numeric data types Subtract dates from one another ONLY (cannot add dates) Add numbers to dates Time functions similarly

10 Null Values The value that’s not a value Missing or unknown *** Not a blank or zero Examples (which represents Null)? ‘ ‘, 000, ‘’, ‘ ‘ Null values can be useful, especially when determining missed values (also when joining tables)


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