Difference between revisions of "SQL Relational operators"

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Relational Operators compare two expressions and evaluate to either True or False.
 
Relational Operators compare two expressions and evaluate to either True or False.
  
{| class="wikitable"
+
{| class="wikitable" width=100%
 
!Operator||Description
 
!Operator||Description
 
|-
 
|-
|=||True if <expression1> and <expression2> are equal, otherwise False
+
|valign="top"|=||True if <expression1> and <expression2> are equal, otherwise False
 
|-
 
|-
|<||True if <expression1> is less than <expression2>, otherwise False
+
|valign="top"|<||True if <expression1> is less than <expression2>, otherwise False
 
|-
 
|-
|<=||True if <expression1> is less than or equal to <expression2>, otherwise False
+
|valign="top"|<=||True if <expression1> is less than or equal to <expression2>, otherwise False
 
|-
 
|-
|>||True if <expression1> is greater than the <expression2>, otherwise False
+
|valign="top"|>||True if <expression1> is greater than the <expression2>, otherwise False
 
|-
 
|-
|>=||True if <expression1> is greater than or equal to <expression2>, otherwise False
+
|valign="top"|>=||True if <expression1> is greater than or equal to <expression2>, otherwise False
 
|-
 
|-
|<>||True if <expression1> and <expression2> are not equal, otherwise False
+
|valign="top"|<>||True if <expression1> and <expression2> are not equal, otherwise False
 
|-
 
|-
|!=||True if <expression1> and <expression2> are not equal, otherwise False
+
|valign="top"|!=||True if <expression1> and <expression2> are not equal, otherwise False
 
|-
 
|-
|#||True if <expression1> and <expression2> are not equal, otherwise False
+
|valign="top"|#||True if <expression1> and <expression2> are not equal, otherwise False
 
|-
 
|-
|$||True if <expression1> is a sub string of <expression2>.  Both <expression1> and <expression2>must be character strings.
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|valign="top"|$||True if <expression1> is a sub string of <expression2>.  Both <expression1> and <expression2>must be character strings.
 
|-
 
|-
|<nowiki>|</nowiki>||True if <expression2> is a sub string of <expression1>.  Both <expression1> and <expression2>must be character strings.
+
|valign="top"|<nowiki>|</nowiki>||True if <expression2> is a sub string of <expression1>.  Both <expression1> and <expression2>must be character strings.
 
|-
 
|-
|==||True if <expression1> and <expression2> match, otherwise False.  Both <expression1> and <expression2>must be character strings.  The <expression2> can contain the wildcards below.
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|valign="top"|==||True if <expression1> and <expression2> match, otherwise False.  Both <expression1> and <expression2>must be character strings.  The <expression2> can contain the wildcards below.
 
|-
 
|-
 
|}
 
|}
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Wildcards for == pattern matching:
 
Wildcards for == pattern matching:
  
{| class="wikitable"
+
{| class="wikitable" width=100%
 
!Operator||Description
 
!Operator||Description
 
|-
 
|-

Revision as of 12:58, 18 January 2013

Purpose

Relational Operators

Syntax

<expression1> operator <expression2>

See Also

INSERT, SQL OPERATORS, SELECT, UPDATE

Description

Relational Operators compare two expressions and evaluate to either True or False.

Operator Description
= True if <expression1> and <expression2> are equal, otherwise False
< True if <expression1> is less than <expression2>, otherwise False
<= True if <expression1> is less than or equal to <expression2>, otherwise False
> True if <expression1> is greater than the <expression2>, otherwise False
>= True if <expression1> is greater than or equal to <expression2>, otherwise False
<> True if <expression1> and <expression2> are not equal, otherwise False
!= True if <expression1> and <expression2> are not equal, otherwise False
# True if <expression1> and <expression2> are not equal, otherwise False
$ True if <expression1> is a sub string of <expression2>. Both <expression1> and <expression2>must be character strings.
| True if <expression2> is a sub string of <expression1>. Both <expression1> and <expression2>must be character strings.
== True if <expression1> and <expression2> match, otherwise False. Both <expression1> and <expression2>must be character strings. The <expression2> can contain the wildcards below.

Wildcards for == pattern matching:

Operator Description
_ Any single character
% Zero or more characters

Example

SELECT name, address, balance, cost*1.15;
FROM accounts;
WHERE paid_date = date();
ORDER BY name, paid_date
 
SELECT name, address, balance, cost*1.15;
FROM accounts;
WHERE paid_date <= date();
ORDER BY name, paid_date
 
SELECT name, address, balance, cost*1.15;
FROM accounts;
WHERE paid_date <> date();
ORDER BY name, paid_date
 
SELECT name, address, balance, cost*1.15;
FROM accounts;
WHERE name == "%inc%";
ORDER BY name, paid_date
 
SELECT name, address, balance, cost*1.15;
FROM accounts;
WHERE name | "inc";
ORDER BY name, paid_date
 
SELECT name, address, balance, cost*1.15;
FROM accounts;
WHERE name $ "BigCo inc, BigCo plc";
ORDER BY name, paid_date