SQL multiple columns WHERE condition

Question

I have table

and very large .csv file (about 1M rows). It contains Columns A, B and C.

I need to extract rows from table where (B = 'a' and C = 'd') or (B = 'b' and C = 'w') or (B = 'c' and C = 'f')

Result will be:

Column A	Column B	Column C
1	a	d
3	c	f

I've tried query like in description, but it's too large for request (1M rows)

Amadan · Accepted Answer · 2023-01-11 04:09:13Z

2

You are basically trying to join on the columns (b, c) manually. However, SQL knows how to do a join more efficiently.

Import the CSV file as a temporary table, analyze it, create a multi-column index on its (b, c), then do a join like this:

SELECT R.*
FROM realTable R
JOIN csvTable C
  ON R.b = C.b AND R.c = C.c;

answered Jan 11, 2023 at 3:50

Amadan

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