On Fri, Mar 2, 2018 at 4:41 PM, Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote:
On 03/02/2018 04:36 PM, Dale Seaburg wrote:
My mind is drawing a blank. Not sure where to go to find the answer. Here is the statement in C#:
sSQL = "SELECT \"Image_Filename\" FROM \"Instruments\" WHERE ";
To finish off the WHERE clause, I need to look at the first 2 letters, like "D:". My question is how do I specify in the WHERE clause, to look at the first 2 characters in the Image_Filename column? What is the correct SQL syntax for looking at just a portion of a column?
SELECT "Image_Filename" FROM "Instruments" WHERE "ImageFilename" LIKE 'D:%';
If you want case insensitive then ILIKE. For more info:
https://www.postgresql.org/docs/10/static/functions-matching .html#FUNCTIONS-LIKE
It's not clear what kind of test you're trying to apply to those first two characters. If you want to pull them out to use in an _expression_ (e.g., if you want to see if they are greater or less than something else), you can use SUBSTRING or LEFT.
SELECT SUBSTRING('abc' FROM 1 FOR 2),LEFT('abc',2),LEFT('abc',2)<'aa' AS is_less,LEFT('abc',2)>'aa' AS is_more;substring | left | is_less | is_more -----------+------+---------+--------- ab | ab | f | t (1 row)Cheers,
Ken
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