I have a MySQL query and I need to SUM the content of a column if the content contains the number 1,
This is what I have but the TotalFails returns 0
SELECT
d.SeqNo,
d.SeqText,
h.UniqueID,
h.SeqID,
h.Room,
IF(h.Status = '1', SUM(h.Status), 0) AS TotalFails
FROM ".$SequenceNo_default." d
LEFT
JOIN ".$Hist." h ON h.SeqID = d.SeqID
WHERE d.SeqActive = 1 AND DATE(CompStamp) BETWEEN DATE( '".$_SESSION['StartDate']."') AND DATE('".$_SESSION['EndDate']."')
GROUP BY h.Room
ORDER BY h.Status ASC
Can any one see where I am going wrong?
Please note that Status is a reserved keyword so you may want to change it to something else like myStatus in the statement above.
Edit
Based upon your updated question, I would rewrite your query as follows (again, avoiding the keyword STATUS by replacing Status with myStatus):
SELECT
d.SeqNo,
d.SeqText,
h.UniqueID,
h.SeqID,
h.Room,
SUM(h.myStatus) AS TotalFails
FROM ".$SequenceNo_default." d
LEFT
JOIN ".$Hist." h ON h.SeqID = d.SeqID
WHERE d.SeqActive = 1 AND DATE(CompStamp) BETWEEN DATE( '".$_SESSION['StartDate']."') AND DATE('".$_SESSION['EndDate']."')
GROUP BY h.Room, h.myStatus
ORDER BY h.myStatus ASC
As a separate side note, this should be a prepared query, rather than including the $_SESSION variable directly into the string. $_SESSION is better than $_POST or $_GET, but for maintaining the code, this would be a good habit (for example, what if the code later changes to $_POST?).
Related
I have two tables, one is for news and the other one is for comments and I want to get the count of the comments whose status has been set as approved.
SELECT
ccc_news . *,
count(if(ccc_news_comments.id = 'approved', ccc_news_comments.id, 0)) AS comments
FROM
ccc_news
LEFT JOIN
ccc_news_comments
ON ccc_news_comments.news_id = ccc_news.news_id
WHERE
`ccc_news`.`category` = 'news_layer2'
AND `ccc_news`.`status` = 'Active'
GROUP BY
ccc_news.news_id
ORDER BY
ccc_news.set_order ASC
LIMIT 20
But the problem with this query is that the minimum value that is fetched for the comments column is 1 whether there is any comment existent corresponding to that news or not.
Any help would be highly appreciable.
Use sum() in place of count()
Try below:
SELECT
ccc_news . * ,
SUM(if(ccc_news_comments.id = 'approved', 1, 0)) AS comments
FROM
ccc_news
LEFT JOIN
ccc_news_comments
ON
ccc_news_comments.news_id = ccc_news.news_id
WHERE
`ccc_news`.`category` = 'news_layer2'
AND `ccc_news`.`status` = 'Active'
GROUP BY
ccc_news.news_id
ORDER BY
ccc_news.set_order ASC
LIMIT 20
Better still (or shorter anyway):
SUM(ccc_news_comments.id = 'approved')
This works since the Boolean type in MySQL is represented as INT 0 and 1, just like in C. (May not be portable across DB systems though.)
As for COALESCE() as mentioned in other answers, many language APIs automatically convert NULL to '' when fetching the value. For example with PHP's mysqli interface it would be safe to run your query without COALESCE().
This should work:
count(if(ccc_news_comments.id = 'approved', ccc_news_comments.id, NULL))
count() only check if the value exists or not. 0 is equivalent to an existent value, so it counts one more, while NULL is like a non-existent value, so is not counted.
Replace this line:
count(if(ccc_news_comments.id = 'approved', ccc_news_comments.id, 0)) AS comments
With this one:
coalesce(sum(ccc_news_comments.id = 'approved'), 0) comments
count(ccc_news_comments.id = 'approved' or null)
More concise
I'm trying to inherit value from previous row (based on correct subscription_id + checking for IS NULL subscription_status), but something goes wrong and I get incorrect value.
Take a look at screenshot.
If I'm not mistaken it also called last non-null puzzle, but examples of possible solution for other DB provide window function with IGNORE NULLS.
But, I'm using MySQL 8.x and it doesn't support this function.
I'm sorry, but SQL fiddle doesn't provide correct text-value for variables in my code :(
https://www.db-fiddle.com/f/wHanqoSCHKJHus5u6BU4DB/4
Or, you can see mistakes here:
SET #history_subscription_status = NULL;
SET #history_subscription_id = 0;
SELECT
c.date,
c.user_id,
c.subscription_id,
sd.subscription_status,
(#history_subscription_id := c.subscription_id) as 'historical_sub_id',
(#history_subscription_status := CASE
WHEN #history_subscription_id = c.subscription_id AND sd.subscription_status IS NULL
THEN #history_subscription_status
ELSE
sd.subscription_status
END
) as 'historical'
FROM
calendar c
LEFT JOIN
subscription_data sd ON sd.date = c.date AND sd.user_id = c.user_id AND sd.subscription_id = c.subscription_id
ORDER BY
c.user_id,
c.subscription_id,
c.date
I expect to get results for this query in this way:
IMPORTANT: I'm going to use this code for a lot of data (about 1 mln rows), so it very important for me to avoid additional select or subquery that can slow down the execution of the query.
I have a table with exchange rate like below
And I am using the maxofdate to pick all these values based on currency code. But the query is giving blank.
Select USDAMOUNT * dbo.EXCHANGERATEAMT
from dbo.Amount_monthly
Left Join dbo.EXCHANGERATE on dbo.Amount_monthly.Currencycode=dbo.EXCHANGERATE.fromcurrencycode
WHERE ValidToDateTime = (Select MAX(ValidToDateTime) from dbo.EXCHANGERATE)
AND dbo.EXCHANGERATE.EXCHANGERATETYPECODE = 'DAY'
Using this statement
CONVERT(DATE,ValidToDateTime) = CONVERT(DATE,GETDATE()-1)
instead of subquery is giving me expected result.
Can someone correct this.
thanks in advance.
If I understand correctly, you need two things. First, the condition for the max() needs to match the condition in the outer query. Second, if you really want a left join, then conditions on the second table need to go in the on clause.
The resulting query looks like:
Select . . .
from dbo.Amount_monthly am Left Join
dbo.EXCHANGERATE er
on am.Currencycode = er.fromcurrencycode and
er.ValidToDateTime = (Select max(er2.ValidToDateTime)
from dbo.EXCHANGERATE er2
where er2.EXCHANGERATETYPECODE = 'DAY'
) and
er.EXCHANGERATETYPECODE = 'DAY';
I would write this using window functions, but that is a separate issue.
Try removing WHERE clause for ValidToDateTime and include it in the JOIN as AND condition
SELECT USDAMOUNT * dbo.EXCHANGERATEAMT
FROM dbo.Amount_monthly
LEFT JOIN dbo.EXCHANGERATE
ON dbo.Amount_monthly.Currencycode = dbo.EXCHANGERATE.fromcurrencycode
AND ValidToDateTime = (SELECT MAX(ValidToDateTime) --remove WHERE clause
FROM dbo.EXCHANGERATE)
AND dbo.EXCHANGERATE.EXCHANGERATETYPECODE = 'DAY';
I cleaned up your query a bit: as the other folks mentioned you needed to close the parentheses around the MAX(Date) sub-query, and if you reference a LEFT JOINed table in the WHERE clause, it behaves like an INNER JOIN, so I changed to in INNER. You also had "dbo" sprinkled in as a field prefix, but that (the namespace) only prefixes a database, not a field. I added the IS NOT NULL check just to avoid SQL giving the "null values were eliminated" SQL warning. I used the aliases "am" for the first table and "er" for the 2nd, which makes it more readable:
SELECT am.USDAMOUNT * er.EXCHANGERATEAMT
FROM dbo.Amount_monthly am
JOIN dbo.EXCHANGERATE er
ON am.Currencycode = er.fromcurrencycode
WHERE er.ValidToDateTime = (SELECT MAX(ValidToDateTime) FROM dbo.EXCHANGERATE WHERE ValidToDateTime IS NOT NULL)
AND er.EXCHANGERATETYPECODE = 'DAY'
If you're paranoid like I am, you might also want to make sure the exchange rate is not zero to avoid a divide-by-zero error.
I'm trying to do a search on serialized post meta values in a wordpress database. I know the structure of the serial string so I can search for the preceding value, get the index and then get the number of characters I want before that index value. I cannot effectively use regexp in this particular query because I would like to sort based on the results. This is what I have so far, but I am failing on the syntax and I think it has to do with trying to use the AS keyword and my grouping the AND statements.
SELECT SQL_CALC_FOUND_ROWS _posts.ID FROM _posts
INNER JOIN _postmeta ON (_posts.ID = _postmeta.post_id)
WHERE 1=1
AND _posts.post_type = 'dog'
AND (_posts.post_status = 'publish')
AND ( (_postmeta.meta_key = '_meta_general'
AND CAST(_postmeta.meta_value AS CHAR)) AS dmet
AND POSITION(';s:6:\"weight' IN dmet) AS ddex
AND MID(dmet ,ddex,10)) AS dres
GROUP BY dres ORDER BY dres ASC LIMIT 0, 10
Well, I'm still having issues with the structure of this thing. The previous code did not work, #fenway, after closer inspection. Here is what I have now. The problem with #fenway's answer is that the MID and POSITION values were being called in the select part of the statement that was selecting "FROM" posts. They are located in postmeta. So I attempted to rearrange the string filtering after the INNER JOIN which is joining the postmeta table to the posts table by id. This is not working. I understand that this question is simply due to a lack of my knowledge in SQL, but I'm trying to learn here.
None of these are working as I want. There are syntactical errors. The purpose of the code is to group the returned query by a value that is inside of a serial(json) string. The method is to search for the following value (n this case it would be - ";s:6:"weight -) When I have the index of this string I want to return the preceding 10 values ( a date xx/xx/xxxx ). I want to label this string (AS dres) and have the result sort by dres. Wordpress gathers the posts from the posts table, then gathers the post meta from the postmeta table. The post meta table is where the json is stored. It is really a simple algorithm, it's just the syntax that is screwing with me.
SELECT SQL_CALC_FOUND_ROWS {$wpdb->posts}.ID
FROM {$wpdb->posts} INNER JOIN {$wpdb->postmeta}
MID(CAST({$wpdb->postmeta}.meta_value AS CHAR),
POSITION(';s:6:\"weight' IN CAST({$wpdb->postmeta}.meta_value AS CHAR) ),10 ) AS dres
ON ({$wpdb->posts}.ID = {$wpdb->postmeta}.post_id)
WHERE 1=1
AND {$wpdb->posts}.post_type = 'dog'
AND ({$wpdb->posts}.post_status = 'publish')
AND {$wpdb->postmeta}.meta_key = '_meta_general'
AND POSITION(';s:6:"weight' IN CAST({$wpdb->postmeta}.meta_value AS CHAR)) > 0
GROUP BY {$wpdb->posts}.ID ORDER BY dres ASC LIMIT 0, 10
You can't use column aliases in your WHERE clause -- what's more, in some cases, those expressions with always evaluate to TRUE, so I don't see why there are there at all.
Perhaps you mean:
SELECT SQL_CALC_FOUND_ROWS
_posts.ID
,MID(
CAST(_postmeta.meta_value AS CHAR),
POSITION(';s:6:\"weight' IN CAST(_postmeta.meta_value AS CHAR) ),
10
) AS dres
FROM _posts
INNER JOIN _postmeta ON (_posts.ID = _postmeta.post_id)
WHERE 1=1
AND _posts.post_type = 'dog' AND _posts.post_status = 'publish'
AND _postmeta.meta_key = '_meta_general'
AND POSITION(';s:6:\"weight' IN CAST(_postmeta.meta_value AS CHAR)) > 0
GROUP BY dres ORDER BY _postmeta.meta_value ASC LIMIT 0, 10
Not quite sure what I'm missing, but my SQL statement is only returning one row.
SELECT
tl.*,
(tl.topic_total_rating/tl.topic_rates) as topic_rating,
COUNT(pl.post_id) - 1 as reply_count,
MIN(pl.post_time) AS topic_time,
MAX(pl.post_time) AS topic_bump
FROM topic_list tl
JOIN post_list pl
ON tl.topic_id=pl.post_parent
WHERE
tl.topic_board_link = %i
AND topic_hidden != 1
ORDER BY %s
I have two tables (post_list and topic_list), and post_list's post_parent links to a topic_list's topic_id.
Instead of returning all the topics (where their board's topic_board_link is n), it only returns one topic.
You would normally need a GROUP BY clause in there. MySQL has different rules from Standard SQL on the subject of when GROUP BY is needed. This is therefore closer to Standard SQL:
SELECT tl.*,
(tl.topic_total_rating/tl.topic_rates) AS topic_rating,
COUNT(pl.post_id) - 1 AS reply_count,
MIN(pl.post_time) AS topic_time,
MAX(pl.post_time) AS topic_bump
FROM topic_list AS tl
JOIN post_list AS pl ON tl.topic_id = pl.post_parent
WHERE tl.topic_board_link = ? -- %i
AND tl.topic_hidden != 1
GROUP BY tl.col1, ..., topic_rating
ORDER BY ? -- %s
In Standard SQL, you would have to list every column in topic_list, plus the non-aggregate value topic_rating (and you might have to list the expression rather than the display label or column alias in the select list).
You also have a restriction condition on 'topic_board_link' which might be limiting your result set to one group. You cannot normally use a placeholder in the ORDER BY clause, either.