Question

I have two tables.

Table A

Column 1     Column 2
CT 3C        10.5 -23.12
OT 5A        11.2 -24.5

Table B

Column 1     Column 2
PRIM         12.3 -24.51, 10.5 -23.12, 61.24 -78.23
SEC          8.7345 -46.1934, 10.49 -49.1834
TERT         18.98 -28.12, 11.23 -24.78, 1.45 -24.11, 11.2 -24.5

Resulting Table after the join:

Column 1      Column 2      Column 3     Column 4
CT 3C         10.5 -23.12   PRIM         12.3 -24.51, 10.5 -23.12, 61.24 -78.23
OT 5A         11.2 -24.5    TERT         18.98 -28.12, 11.23 -24.78, 1.45 -24.11, 11.2 -24.5

Is there a way to this match without splitting the contents of ‘column 2 in Table B’ into separate columns? The contents in ‘Column 2 of Table B’ are delimited by ‘,’.

10.5 -23.12 should match with 12.3 -24.51, 10.5 -23.12, 61.24 -78.23 as it is contained in the list of values present in it.

I can’t split them into separate columns because in some cases there are as many as 300 distinct values in it separated by a ‘,’

Answer 1

Short Term Solution

Use the FIND_IN_SET function:

SELECT a.column1, a.column2,
       b.column1, b.column2
  FROM TABLE_A a
  JOIN TABLE_B b ON FIND_IN_SET(a.column2, b.column2) > 0

Long Term Solution

Denormalized data should only be stored as a performance improvement, after it’s been determined necessary — not before.

You need a many-to-many table between TABLE_A and TABLE_B to hold the relationships represented in the comma separated lists.