Question

I have a table in my database in SQLITE which has x and y co-ordinates in location field as (10,10).
I want to use the x co-ordinate and y co-ordinate separately by using a select query. I know we can use subtr and charAtIndex to locate the position but I am not sure how to do it ?
I am new to sqlite and need some help to sort this out.

Answer 1

SQLite’s string functions are fairly limited but you abuse its implicit type conversions to split your string. Something like this should do it:

select xy + 0 as x,
       substr(xy, length(xy + 0) + 2) as y
from some_table

That should work as long as you don’t have any leading zeros or spaces or internal spaces. Adding zero turns the value into a number so '10,5' + 0 becomes just 10; then calling length on that turns it back into a string and gives you the string length, then adjust that to account for the comma (+1) and length-to-offset (+1) change and you’ll get your 5 out of '10,5'.

For example:

sqlite> select '10,5' + 0 as x, substr('10,5', length('10,5' + 0) + 2) as y;
x|y
10|5

That said, you really should redesign your schema to have separate columns for the X and Y coordinates, storing structured data inside a single column is generally a bad idea.

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Update for comments: SQLite will also let you do things like this:

select value,
       xy + 0 as x,
       substr(xy, length(xy + 0) + 2) as y
from some_table
where x < 2000
  and y < 2000

or even:

select value
from some_table
where (xy + 0) < 2000
  and substr(xy, length(xy + 0) + 2) < 2000

These sorts of queries will end up doing full table scans though so they might be too slow for you. Fixing your schema to have separate X and Y coordinate columns OTOH would give you fast queries.