Mysql – HELP with SQL WHERE syntax

MySQLselect

I have to pull out a range of entries from a database, all based around two pieces of data. In itself that's fine. An example of the data is:

Record   ID    Tags
1        1423  Day, Sun, Warm
2        1423  Day, Sun, Wet
3        1742  Night, Warm
4        2743  Night, Warm, Dry, Stars
5        4832  Sunrise, Bright, Clear, Cool

Now in the above data, the ID is an internal company ID, but Record is a unique DB ID. There are 2,500 rows of similar data in the database, with other data that's not related to this query. Now we need to pull the data in the following style, written here in a symbolic, rather than specific SQL so people can understand it. I've included brackets to emphasis which parts must match:

WHERE (ID=1423 AND tags contains Warm) 
OR WHERE (ID=2743 AND Tags contains Dry) 
OR WHERE (ID=4832 AND Tags contains Cold)

The question is how do I get the SQL statement to work right? I've tried

SELECT DISTINCT ID 
FROM DBTABLE 
WHERE ID=2743 AND Tags LIKE '%Warm%' 
    OR ID=4832 AND Tags LIKE '%Cool%'

But it doesn't seem to return the correct records. I have a specific query which I know will return 5 records, but every time it returns more, including ones that don't match. I'm thinking the SQL is mixing up, for example, where ID=2743 AND (tags like warm or 2743) AND Tags like dry or 4832 etc…

Can anyone point me in the right direction. In essence it is multiple where statements, where each statement has to match an ID and have a 'LIKE' tag. but the statement can match one or more of the given WHERE statements. Does that make sense?

Best Answer

As Martin Smith and dezso commented, you can add parentheses to your query to be explicit in your intent since they can change how the where clause is evaluated:

SELECT DISTINCT ID AS IDs
FROM DBTABLE
WHERE ((ID = 1423) AND (Tags LIKE '%Warm%'))
OR ((ID = 2743) AND (Tags LIKE '%Dry%'))
OR ((ID = 4832) AND (Tags LIKE '%Cool%'))

This returns a 3-record result set containing 1423, 2743 & 4832 from your example data.

Parentheses can also make your SQL queries more readable and maintainable.

Related Solutions

Mysql – How to improve the SQL statement with weekly results with week starting on Thursday or any other day of the week

Here is a query I wrote up to give you the most recent thursday and the ending wednesday

SELECT thuwk_beg + INTERVAL 0 second thu_beg,
thuwk_beg + INTERVAL 604799 second wed_end
FROM (SELECT (DATE(NOW()) - INTERVAL daysbacktothursday DAY) thuwk_beg
FROM (SELECT SUBSTR('3456012',wkndx,1) daysbacktothursday
FROM (SELECT DAYOFWEEK(dt) wkndx FROM (SELECT DATE(NOW()) dt) AAAA) AAA) AA) A;

Here is an example for today, 2011-09-21

mysql> SELECT
    -> thuwk_beg + INTERVAL 0 second thu_beg,
    -> thuwk_beg + INTERVAL 604799 second wed_end
    -> FROM (SELECT (DATE(NOW()) - INTERVAL daysbacktothursday DAY) thuwk_beg
    -> FROM (SELECT SUBSTR('3456012',wkndx,1) daysbacktothursday
    -> FROM (SELECT DAYOFWEEK(dt) wkndx FROM (SELECT DATE(NOW()) dt) AAAA) AAA) AA) A;
+---------------------+---------------------+
| thu_beg             | wed_end             |
+---------------------+---------------------+
| 2011-09-15 00:00:00 | 2011-09-21 23:59:59 |
+---------------------+---------------------+
1 row in set (0.00 sec)

Just replace the NOW() function calls with whatever datetime you like and you will have the week starting Thursday all the time for the give datetime you choose.

Here is another example using the specific date '2011-01-01'

mysql> SELECT
    -> thuwk_beg + INTERVAL 0 second thu_beg,
    -> thuwk_beg + INTERVAL 604799 second wed_end
    -> FROM (SELECT (DATE('2011-01-01') - INTERVAL daysbacktothursday DAY) thuwk_beg
    -> FROM (SELECT SUBSTR('3456012',wkndx,1) daysbacktothursday
    -> FROM (SELECT DAYOFWEEK(dt) wkndx FROM (SELECT DATE('2011-01-01') dt) AAAA) AAA) AA) A;
+---------------------+---------------------+
| thu_beg             | wed_end             |
+---------------------+---------------------+
| 2010-12-30 00:00:00 | 2011-01-05 23:59:59 |
+---------------------+---------------------+
1 row in set (0.00 sec)

Your query of table referencing today would resemble something like this:

SELECT * from `table`,
(SELECT thuwk_beg + INTERVAL 0 second thu_beg,
thuwk_beg + INTERVAL 604799 second wed_end
FROM (SELECT (DATE(NOW()) - INTERVAL daysbacktothursday DAY) thuwk_beg
FROM (SELECT SUBSTR('3456012',wkndx,1) daysbacktothursday
FROM (SELECT DAYOFWEEK(dt) wkndx FROM (SELECT DATE(NOW()) dt) AAAA) AAA) AA) A) M
WHERE `date` >= thu_beg
AND `date` <= wed_end;

Give it a Try !!!

UPDATE 2011-09-22 16:27 EDT

This was my proposed query for marking Thu-Wed.

SELECT thuwk_beg + INTERVAL 0 second thu_beg,
thuwk_beg + INTERVAL 604799 second wed_end
FROM (SELECT (DATE(NOW()) - INTERVAL daysbacktothursday DAY) thuwk_beg
FROM (SELECT SUBSTR('3456012',wkndx,1) daysbacktothursday
FROM (SELECT DAYOFWEEK(dt) wkndx FROM (SELECT DATE(NOW()) dt) AAAA) AAA) AA) A;

How about other weeks ???

(SELECT SUBSTR('6012345',wkndx,1) does the week starting Mon ending Sun
(SELECT SUBSTR('5601234',wkndx,1) does the week starting Tue ending Mon
(SELECT SUBSTR('4560123',wkndx,1) does the week starting Wed ending Tue
(SELECT SUBSTR('3456012',wkndx,1) does the week starting Thu ending Wed
(SELECT SUBSTR('2345601',wkndx,1) does the week starting Fri ending Thu
(SELECT SUBSTR('1234560',wkndx,1) does the week starting Sat ending Fri
(SELECT SUBSTR('0123456',wkndx,1) does the week starting Sun ending Sat

Sql-server – How to avoid duplicating information in a series of nested SELECT statements

;WITH x AS 
(
  SELECT g.guestid, e.[year], e.run, c = COUNT(*)
  FROM dbo.guest AS g
  INNER JOIN dbo.[order] AS o
  ON g.guestid = o.guestid
  INNER JOIN dbo.eventseat AS es
  ON o.orderid = es.orderid
  INNER JOIN dbo.event2 AS e
  ON e.eventid = es.eventid
  WHERE e.incometype = 'T'
  AND e.eventtype in ('SS', 'BMF')
  AND es.status in ('2','4')
  AND es.price NOT IN ( '0.00', '5.00')
  AND e.[year] = '2010'
  AND e.run IN ('SS-DANCE', 'SS-FILM', 'SS-OPERA')
  GROUP BY g.guestid, e.[Year], e.run
),
y AS 
(
  SELECT * FROM x PIVOT (MAX(c) FOR run IN 
  ([SS-DANCE],[SS-FILM],[SS-OPERA])) AS z
)
SELECT y.guestid, y.[year], g.[first], g.[last], 
  [SS-DANCE] = COALESCE(y.[SS-DANCE], 0), 
  [SS-FILM]  = COALESCE(y.[SS-FILM], 0), 
  [SS-OPERA] = COALESCE(y.[SS-OPERA], 0)
FROM y 
INNER JOIN dbo.guest AS g
ON y.guestid = g.guestid;

I'm not sure if my where clause is going to work for you as written. This currently assumes you only care about these three types (dance, film and opera) and you only care about the year 2010. If you need to cross years you can remove that WHERE clause. If you only care about dance in 2010 and film in any year you'll need to write a more complex set of where clauses.

Some comments:

try to avoid reserved words like order, year, first and last. These only complicate matters because they need to be enclosed in square brackets (which are preferable over "double quotes" mostly for readability and unambiguity).
always use dbo. (or whatever schema prefix is appropriate).
as I suggested above, stick to explicit INNER JOIN syntax. FROM x, y, z is for the birds.

Best Answer

Related Solutions

Mysql – How to improve the SQL statement with weekly results with week starting on Thursday or any other day of the week

Sql-server – How to avoid duplicating information in a series of nested SELECT statements

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