Re: SQL syntax - Mailing list pgsql-general

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

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)

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