Converting MySQL Queries to SQL Server - mysql

Question

Can anyone please help converting the MySQL query below to SQL Server.
The 'DATE_FORMAT' and the LIMIT:limit are the problem.
SELECT
DATE_FORMAT(e.eventTime, '%m/%d/%Y %h:%i:%s %p') eventTime,
e.displayPath,
SUBSTRING_INDEX(source, '/alm:', -1) name,
e.eventType,
CASE WHEN e.priority = 0 THEN 'Diagnostic' WHEN e.priority = 1 THEN 'Low' WHEN e.priority = 2 THEN 'Medium' WHEN e.priority = 3 THEN 'High' WHEN e.priority = 4 THEN 'Critical' ELSE '' END priority,
COALESCE(COALESCE(COALESCE(d.intvalue, d.floatvalue), d.strvalue), '') eventValue,
COALESCE(ack.strvalue, '') ackUser
FROM
alarm_events e
LEFT JOIN alarm_event_data d ON d.id = e.id AND d.propname = 'eventValue'
LEFT JOIN alarm_event_data ack ON ack.id = e.id AND ack.propname = 'ackUser'
WHERE
eventtime BETWEEN :startDate AND :endDate AND priority BETWEEN :minPriority AND :maxPriority AND
((:active AND e.eventtype = 0) OR (:clear AND e.eventtype = 1) OR (:ack AND e.eventtype = 2))
ORDER BY
e.eventTime DESC
LIMIT :limit

Answer 1

Variables in SQL use an # instead of the : so you would need to adjust for that and populate your variables from the application.
Instead of the LIMIT parameter, you'd begin the query with a SELECT TOP #limit
The SUBSTRING_INDEX function needs to be adjusted to a standard SUBSTRING and PATINDEX function.
You would need to use the FORMAT() instead of DATE_FORMAT() function ().
As mentioned in the comments, using additional COALESCE() functions in SQL Server is unnecessary.
So the final query would look something like this (with variables to be set by your calling program):
SELECT TOP (#limit)
FORMAT(e.eventTime, 'M/d/yy hh:mm:ss tt') eventTime,
e.displayPath,
SUBSTRING(source, patindex(source,'/alm:'),len(source)) name,
e.eventType,
CASE WHEN e.priority = 0 THEN 'Diagnostic' WHEN e.priority = 1 THEN 'Low' WHEN e.priority = 2 THEN 'Medium' WHEN e.priority = 3 THEN 'High' WHEN e.priority = 4 THEN 'Critical' ELSE '' END priority,
COALESCE(d.intvalue, d.floatvalue, d.strvalue, '') eventValue,
COALESCE(ack.strvalue, '') ackUser
FROM
alarm_events e
LEFT JOIN alarm_event_data d ON d.id = e.id AND d.propname = 'eventValue'
LEFT JOIN alarm_event_data ack ON ack.id = e.id AND ack.propname = 'ackUser'
WHERE
eventtime BETWEEN #startDate AND #endDate AND priority BETWEEN #minPriority AND #maxPriority AND
((#active AND e.eventtype = 0) OR (#clear AND e.eventtype = 1) OR (#ack AND e.eventtype = 2))
ORDER BY
e.eventTime DESC