Database

SELECT DISTINCT
    b.event_id,
    b.user_ID,
    b.date,
    b.Time
FROM 
    quadrantids2017 AS a
    JOIN quadrantids2017 AS b
WHERE 
    a.`date` = b.`date`
AND 
    a.user_ID != b.user_ID
AND 
    time_to_sec(a.`Time`) - time_to_sec(b.`Time`) BETWEEN -30 AND 30

SELECT
b.event_id AS a,
b.user_ID AS a,
b.date AS a,
b.Time AS a
FROM quadrantids2017 AS a
JOIN quadrantids2017 AS b
WHERE a.`date` = b.`date`

AND time_to_sec(a.`Time`) - time_to_sec(b.`Time`) BETWEEN -30 AND 30

AND a.event_id != b.event_id

AND a.user_ID != b.user_ID

AND a.user_ID = b.user_ID

SELECT
b.event_id AS a,
b.user_ID AS a,
b.date AS a,
b.Time AS a
FROM quadrantids2017 AS a
JOIN quadrantids2017 AS b
WHERE a.`date` = b.`date`
AND a.event_id != b.event_id
AND a.user_ID != b.user_ID
AND time_to_sec(a.`Time`) - time_to_sec(b.`Time`) BETWEEN -30 AND 30

1. Always create your databases using a case-insensitive collation, and use a case-sensitive collation on individual columns;
2. Always write your scripts using the case of the table and columns names as defined when they were created;

Quote:

that would have been a breaking change

0x01AA wrote:

is it not MS who is breaking the SQL Standard with this?

Quote:

's the "user" ids / keys that get transported between systems; so they better match (case-wise); unless it's "universal", like an email.