sql select using substring

[mackin]

I have an array of the outcodes of UK postcodes - so LA12, LA13 etc.....
I also have a table of businesses, one of the columns being est_postcode - which has full UK postcodes - i.e - LA13 9UT etc.

so the variable $matches is created from the data stored in $postcode_radius - which works fine. (OUTCODES)

I then want to use the array to SELECT matching Postcodes from the businesses - but need to trim the last 3 characters from the est_postcode - i used the code below but nothing happens - i feel that the SUBSTRING part isnt correct - any advice??

$matches = implode(', ', array_unique($postcode_radius));

//echo $matches; // just checking that the variable looks right


$sql2 = "SELECT * FROM businesses WHERE SUBSTRING(est_postcode , -3) = '".$matches."'";

$result2 = mysql_query($sql2) or die('query failed: ' . mysql_error());

while ($row2 = mysql_fetch_array($result2, MYSQL_ASSOC))
{ 

  echo $row2["est_postcode"], $row2["est_landline"];

} 

[dagon]

SELECT SUBSTRING('LA13 9UT' , -3) = "9UT"

SELECT SUBSTRING('LA13 9UT' , 1,4) = "LA13"

[cretaceous]

UK postcodes are inconsistent so some are 2 3, some 3 3 and some as sample above are 4 3
so Dagon's suggestion won't work on them all
- sorry I don't have a solution

[mackin]

I got to this in the end and it works well - takes everything before the space in the postcode

$matches = implode("', '", array_unique($postcode_radius));

echo $matches;


$sql2 = "SELECT * FROM hotels WHERE (SUBSTRING_INDEX(est_postcode, ' ', 1)) IN ('$matches')";

$result2 = mysql_query($sql2) or die('query failed: ' . mysql_error());

while ($row = mysql_fetch_array($result2, MYSQL_ASSOC))
{ 

  echo $row["est_postcode"] ."<br>". $row["est_landline"];

} 

[dagon]

split on space? I'm not 100% clear as to the 2 value sets you are trying to compare

SELECT SUBSTRING_INDEX( "LA13 9UT" , ' ', 1 ) =LA13

[dagon]

i posted with out refreshing the page, glad you solved it.