Question 20047 in Mysql Question posted in
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How to combine multiple dependent exists queries into a single query? – Mysql

I have two queries that I want to run against a certain type of product, to check whether a product exists with certain specifications.

Therefore I first want to check if a product contains a type=A, and if so check again if it either contains type=B or C.
How can I combine this both into a single query?

table cars:

id;product;type
0;car;A
1;car;B
2;car;C

Current two-step SQL:

SELECT 1 FROM cars where product = 'car' and type = 'A';

if so:

SELECT 1 FROM cars where product = 'car' AND (type = 'B' OR type = 'C');
Tags:

2

Answers


  1. 0

    It sounds like you need to combine them with exists, such as

    select *
from t
where product = 'car' and type = 'A'
and exists (
  select * from t t2
  where t2.product = t.product and t2.type in ('B', 'C')
);
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  2. 0

    Assuming product is "grouping" field in your table you might need something like this.

    SELCET * FROM cars c
WHERE EXISTS(SELECT 1 FROM cars where product = c.product and type = 'A')
AND EXISTS(SELECT 1 FROM cars where product = c.product AND type IN ('B', 'C'))
AND c.product = 'car'
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