Tutorial Addendum on SQL - Operations and Expressions
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This affiliate describes:
- Expressions.
- Arithmetic operations.
- Predicate operations.
- Date and time operations.
- Operation examples.
All addendum in affiliate are based on SQL-92 and MySQL server.
Value Expressions
Value Expressions: Syntax forms to accurate operations adjoin data values. SQL
divides amount expressions into several categories: numeric expressions, appearance string
expressions, bit cord expressions, date and time expressions, and time breach
expressions.
1. Numeric amount expressions are operations that absorb numeric values.
Examples:
1 + 1
2 / 3
100 * (1 + 0.05) * (1 + 0.06)
2. Appearance cord expressions are operations that absorb appearance strings.
Examples:
Accost || world! -- Concatenation, not accurate by MySQL
3. Bit cord expressions are operations that absorb bit strings.
Examples:
~ x 01 -- Negation
3. Date and time expressions are operations that absorb data and time values,
and time breach values. Examples:
date 1999-01-01 + breach 1 year; -- abacus 1 year
timestamp 1999-01-01 01:02:03 + breach 1 minute -- abacus 1 minute
Since expressions are create up by operations, let s attending at some of the frequently used
operations.
Arithmetic Operations
As any additional computer languages, SQL defines 4 addition operations:
- Addition: numeric_value + numeric_value
- Subtraction: numeric_value - numeric_value
- Multiplication: numeric_value * numeric_value
- Division: numeric_value / numeric_value
- Integer division: numeric_value DIV numeric_value
- Modulo: numeric_value MOD numeric_value
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Also see ...
Predicate OperationsPredicate operations are operations that can be evaluated to accord a action of true or false:1. "Comparison" Predicates: Compares
Operation ExamplesExample 1 NumericOps.sql NumericOps.sql Absorb (c) 1999 by Dr. Yang SELECT 1 + 2 AS LINE_1;SELECT 2 / 3 AS LINE_2;
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Here is a simple analysis on stored action the MySQL applicant tool: mysql USE test; mysql DELIMITER / ;mysql Make Action Msg() BEGIN Baddest CURRENT_TIME() AS Time;br
This affiliate describes:Local variables in stored procedures.Execution breeze ascendancy statements.Cursor accompanying statements.br
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