Difference between revisions of "CAST"

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(Created page with "<table align='right' border='1'> <caption>Compatibility</caption> <tr><th colspan='3'>CAST(expr AS type)</th></tr> <tr><td align='center'>'''Engine'''</td><td align='center'>'...")
 
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You can also CAST a date to a string to extract components using SUBSTRING or make up another date.   
 
You can also CAST a date to a string to extract components using SUBSTRING or make up another date.   
 
<source lang='sql' class='def'>
 
<source lang='sql' class='def'>
SELECT CAST(population/1000000 AS DECIMAL(8,1)) AS a
+
SELECT CAST(population/1000000  
 +
      AS DECIMAL(8,1)) AS a
 
       ,population/1000000 AS b
 
       ,population/1000000 AS b
 
   FROM bbc
 
   FROM bbc

Revision as of 12:54, 13 July 2012

Compatibility
CAST(expr AS type)
EngineOKAlternative
ingresYes
mysqlYes
oracleYes
postgresYes
sqlserverYes

CAST

CAST allows you to convert from one type to another.

Often a CAST is implicit - for example if you concatenate a string with a number the number will be automatically changed to a string. However sometimes you need to make the CAST explicit.

 CAST(expr TO type) 

In this example we get the population in millions by casting the floating point value to DECIMAL(8,1) - this ensures one decimal place of accuracy. You can also CAST a date to a string to extract components using SUBSTRING or make up another date.

SELECT CAST(population/1000000 
       AS DECIMAL(8,1)) AS a
      ,population/1000000 AS b
  FROM bbc

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