I currently have a query where I delete a record on call, however after other consideration I would rather just update the record on a is_deleted basis so that I can always have a record of whats been in the system, and or undelete that record at a later time.
My current query:
$delete=mysql_query("DELETE FROM pin_status_types WHERE pinstatus_id='$delete'");
Instead of deleteing the record, i would rather change a value in a column from 0 to 1.
0 = false (not deleted)
1 = true (is deleted)
Correct me if I wrong, but wouldnt I do (Note; I added table. and column. to for note purposes.) something like below to achieve what I am after?
$delete=mysql_query("UPDATE table.pin_status_types SET column.is_deleted = 1 WHERE pinstatus_id='$delete'");
Update your query to:
mysql_query("UPDATE pin_status_types SET is_deleted = 1, date_deleted = NOW() WHERE pinstatus_id = '{$delete}'"
Also, as David suggested in comments, you might want to add timestamp for when a record was deleted for audit purposed.
Update: changed query to cover the issue raised in your comment. Make the date_deleted column default to 0 instead on CURRENT_TIMESTAMP. See this question for more details on that.
Please learn about and use PDO going forward
Related
I have this query:
UPDATE phonecalls
SET Called = "Yes"
WHERE PhoneNumber = "999 29-4655"
My table is phonecalls, I have a column named PhoneNumber. All I want to update is a column named Called to "yes".
Any idea what I am doing wrong? when I return my query it says 0 rows affected.
If the such value already exists, mysql won't change it and will therefore return "0 rows affected". So be sure to also check the current value of called
Another reason for 0 affected rows that I have observed: wrong data type. If the column you want to update is an integer or boolean, and you set it to a string, it won't be updated - but you will also get no error.
To sum up the other strategies/ideas from this post:
Check with a SELECT statement, whether your WHERE works and returns results.
Check whether your columns do already have the value you want to set.
Check if your desired value suits the data type of the column.
If the values are the same, MySQL will not update the row (without triggering any warning or error), so the affected row count will be 0.
The problem might be that there are no records with PhoneNumber == "999 29-4655".
Try this query:
SELECT * FROM phonecalls where PhoneNumber = '999 29-4655'
If it doesn't return anything, then there are no rows that match.
For the benefit of anyone here from Google, this problem was caused by me because I was trying to append to an empty field using CONCAT().
UPDATE example SET data=CONCAT(data, 'more');
If data is NULL, then CONCAT() returns NULL (ignoring the second parameter), so the value does not change (updating a NULL value to be a NULL value), hence the 0 rows updated.
In this case changing to the CONCAT_WS() function instead fixed the problem.
Try select count(*) from phonecalls where PhoneNumber = "999 29-4655"; That will give you the number of matching rows. If the result is 0, then there isn't a row in the database that matches.-
Check to make sure this returns some result.
SELECT * FROM phonecalls WHERE PhoneNumber = '999 29-4655'
If it doesn't return any result than the filter WHERE PhoneNumber = '999 29-4655' is not correct.
Does it say Rows matched: 1 Changed: 0 Warnings: 0? Then maybe it's already set to that value.
Did you try single quotes vs. double quotes?
"999 29-4655" is the space a space or a tab and is it consistent in your query and the database?
That's my sugestion:
UPDATE `phonecalls` SET `Called` = 'yeah!' WHERE `PhoneNumber` = '999 29-4655' AND `Called` != 'yeah!'
And make sure with the case-sensitive name of table and field`s.
Just ran into an obscure case of this. Our code reads a list of records from the database, changes a column, and writes them back one by one. The UPDATE's WHERE clause contains only two conditions: WHERE key=? AND last_update_dt=?. (The timestamp check is for optimistic locking: if the record is changed by another process before we write ours, 0 rows are updated and we throw an error.)
But for one particular row the UPDATE was failing- zero rows effected.
After much hair-pulling I noticed that the timestamp for the row was 2019-03-10 02:59. In much of the U.S. that timestamp wouldn't exist- Daylight Savings Time causes the time to skip directly from 2:00 to 3:00. So I guessed that during the round trip from MySQL to Java back to MySQL, some part of the code was interpreting that timestamp differently from the rest, making the timestamps in the WHERE clause not match.
Changing the row's timestamp by one hour avoided the problem.
(Of course, the correct fix is to abolish Daylight Savings Time. I created a Jira but the U.S. Government has not responded to it yet.)
In my case, I was trying to update a column of text to correct a truncation problem with it. Trying to update to the correct text was yielding 0 rows updated because the text in the row wasn't changing.
Once I extended the column in the table structure to accommodate for the correct number of characters, I was able to see the desired results.
I have this query:
UPDATE phonecalls
SET Called = "Yes"
WHERE PhoneNumber = "999 29-4655"
My table is phonecalls, I have a column named PhoneNumber. All I want to update is a column named Called to "yes".
Any idea what I am doing wrong? when I return my query it says 0 rows affected.
If the such value already exists, mysql won't change it and will therefore return "0 rows affected". So be sure to also check the current value of called
Another reason for 0 affected rows that I have observed: wrong data type. If the column you want to update is an integer or boolean, and you set it to a string, it won't be updated - but you will also get no error.
To sum up the other strategies/ideas from this post:
Check with a SELECT statement, whether your WHERE works and returns results.
Check whether your columns do already have the value you want to set.
Check if your desired value suits the data type of the column.
If the values are the same, MySQL will not update the row (without triggering any warning or error), so the affected row count will be 0.
The problem might be that there are no records with PhoneNumber == "999 29-4655".
Try this query:
SELECT * FROM phonecalls where PhoneNumber = '999 29-4655'
If it doesn't return anything, then there are no rows that match.
For the benefit of anyone here from Google, this problem was caused by me because I was trying to append to an empty field using CONCAT().
UPDATE example SET data=CONCAT(data, 'more');
If data is NULL, then CONCAT() returns NULL (ignoring the second parameter), so the value does not change (updating a NULL value to be a NULL value), hence the 0 rows updated.
In this case changing to the CONCAT_WS() function instead fixed the problem.
Try select count(*) from phonecalls where PhoneNumber = "999 29-4655"; That will give you the number of matching rows. If the result is 0, then there isn't a row in the database that matches.-
Check to make sure this returns some result.
SELECT * FROM phonecalls WHERE PhoneNumber = '999 29-4655'
If it doesn't return any result than the filter WHERE PhoneNumber = '999 29-4655' is not correct.
Does it say Rows matched: 1 Changed: 0 Warnings: 0? Then maybe it's already set to that value.
Did you try single quotes vs. double quotes?
"999 29-4655" is the space a space or a tab and is it consistent in your query and the database?
That's my sugestion:
UPDATE `phonecalls` SET `Called` = 'yeah!' WHERE `PhoneNumber` = '999 29-4655' AND `Called` != 'yeah!'
And make sure with the case-sensitive name of table and field`s.
Just ran into an obscure case of this. Our code reads a list of records from the database, changes a column, and writes them back one by one. The UPDATE's WHERE clause contains only two conditions: WHERE key=? AND last_update_dt=?. (The timestamp check is for optimistic locking: if the record is changed by another process before we write ours, 0 rows are updated and we throw an error.)
But for one particular row the UPDATE was failing- zero rows effected.
After much hair-pulling I noticed that the timestamp for the row was 2019-03-10 02:59. In much of the U.S. that timestamp wouldn't exist- Daylight Savings Time causes the time to skip directly from 2:00 to 3:00. So I guessed that during the round trip from MySQL to Java back to MySQL, some part of the code was interpreting that timestamp differently from the rest, making the timestamps in the WHERE clause not match.
Changing the row's timestamp by one hour avoided the problem.
(Of course, the correct fix is to abolish Daylight Savings Time. I created a Jira but the U.S. Government has not responded to it yet.)
In my case, I was trying to update a column of text to correct a truncation problem with it. Trying to update to the correct text was yielding 0 rows updated because the text in the row wasn't changing.
Once I extended the column in the table structure to accommodate for the correct number of characters, I was able to see the desired results.
I have this query:
UPDATE phonecalls
SET Called = "Yes"
WHERE PhoneNumber = "999 29-4655"
My table is phonecalls, I have a column named PhoneNumber. All I want to update is a column named Called to "yes".
Any idea what I am doing wrong? when I return my query it says 0 rows affected.
If the such value already exists, mysql won't change it and will therefore return "0 rows affected". So be sure to also check the current value of called
Another reason for 0 affected rows that I have observed: wrong data type. If the column you want to update is an integer or boolean, and you set it to a string, it won't be updated - but you will also get no error.
To sum up the other strategies/ideas from this post:
Check with a SELECT statement, whether your WHERE works and returns results.
Check whether your columns do already have the value you want to set.
Check if your desired value suits the data type of the column.
If the values are the same, MySQL will not update the row (without triggering any warning or error), so the affected row count will be 0.
The problem might be that there are no records with PhoneNumber == "999 29-4655".
Try this query:
SELECT * FROM phonecalls where PhoneNumber = '999 29-4655'
If it doesn't return anything, then there are no rows that match.
For the benefit of anyone here from Google, this problem was caused by me because I was trying to append to an empty field using CONCAT().
UPDATE example SET data=CONCAT(data, 'more');
If data is NULL, then CONCAT() returns NULL (ignoring the second parameter), so the value does not change (updating a NULL value to be a NULL value), hence the 0 rows updated.
In this case changing to the CONCAT_WS() function instead fixed the problem.
Try select count(*) from phonecalls where PhoneNumber = "999 29-4655"; That will give you the number of matching rows. If the result is 0, then there isn't a row in the database that matches.-
Check to make sure this returns some result.
SELECT * FROM phonecalls WHERE PhoneNumber = '999 29-4655'
If it doesn't return any result than the filter WHERE PhoneNumber = '999 29-4655' is not correct.
Does it say Rows matched: 1 Changed: 0 Warnings: 0? Then maybe it's already set to that value.
Did you try single quotes vs. double quotes?
"999 29-4655" is the space a space or a tab and is it consistent in your query and the database?
That's my sugestion:
UPDATE `phonecalls` SET `Called` = 'yeah!' WHERE `PhoneNumber` = '999 29-4655' AND `Called` != 'yeah!'
And make sure with the case-sensitive name of table and field`s.
Just ran into an obscure case of this. Our code reads a list of records from the database, changes a column, and writes them back one by one. The UPDATE's WHERE clause contains only two conditions: WHERE key=? AND last_update_dt=?. (The timestamp check is for optimistic locking: if the record is changed by another process before we write ours, 0 rows are updated and we throw an error.)
But for one particular row the UPDATE was failing- zero rows effected.
After much hair-pulling I noticed that the timestamp for the row was 2019-03-10 02:59. In much of the U.S. that timestamp wouldn't exist- Daylight Savings Time causes the time to skip directly from 2:00 to 3:00. So I guessed that during the round trip from MySQL to Java back to MySQL, some part of the code was interpreting that timestamp differently from the rest, making the timestamps in the WHERE clause not match.
Changing the row's timestamp by one hour avoided the problem.
(Of course, the correct fix is to abolish Daylight Savings Time. I created a Jira but the U.S. Government has not responded to it yet.)
In my case, I was trying to update a column of text to correct a truncation problem with it. Trying to update to the correct text was yielding 0 rows updated because the text in the row wasn't changing.
Once I extended the column in the table structure to accommodate for the correct number of characters, I was able to see the desired results.
I'm trying to set some options to be active/inactive and I'm using a column called active which will either be 1 or 0.
Is there a better way to make all 0 except one which will equal 1 and be determined by form submission besides running two queries?
Right now I have this:
mysql_query("UPDATE customizer SET active='1' WHERE text_color='{$text_color}'");
But eventually they'll all be 1.
UPDATE `customizer` SET `active` = (`text_color` = '{$text_color}')
Performs a comparison, which returns 1 if true, 0 if false, and puts that result in the active column.
Consider changing your database structure, though. It would be much better for consistency to have active_colour saved with your user data or something.
I am having a wee problem, and I am sure there is a more convenient/simpler way to achieve the solution, but all searches are throw in up a blanks at the moment !
I have a mysql db that is regularly updated by php page [ via a cron job ] this adds or deletes entries as appropriate.
My issue is that I also need to check if any details [ie the phone number or similar] for the entry have changed, but doing this at every call is not possible [ not only does is seem to me to be overkill, but I am restricted by a 3rd party api call limit] Plus this is not critical info.
So I was thinking it might be best to just check one entry per page call, and iterate through the rows/entires with each successive page call.
What would be the best way of doing this, ie keeping track of which entry/row in the table that the should be checked next?
I have 2 ideas of how to implement this:
1 ) The id of current row could be save to a file on the server [ surely not the best way]
2) an extra boolean field [check] is add to the table, set to True on the first entry and false to all other.
Then on each page call it;
finds 'where check = TRUE'
runs the update check on this row,
'set check = FALSE'
'set [the next row] check = TRUE'
Si this the best way to do this, or does anyone have any better sugestion ?
thanks in advance !
.k
PS sorry about the title
Not sure if this is a good solution, but if I have to make nightly massive updates, I'll write the updates to a new blank table, then do a SQL select to join the tables and tell me where they are different, then do another SQL UPDATE like
UPDATE table, temptable
SET table.col1=temptable.col1, table.col2=temptable.col2 ......
WHERE table.id = temptable.id;
You can store the timestamp that a row is updated implicitly using ON UPDATE CURRENT_TIMESTAMP [http://dev.mysql.com/doc/refman/5.0/en/timestamp.html] or explicitly in your update SQL. Then all you need to do is select the row(s) with the lowest timestamp (using ORDER BY and LIMIT) and you have the next row to process. So long as you ensure that the timestamp is updated each time.
e.g. Say you used the field last_polled_on TIMESTAMP to store the time you polled a row.
Your insert looks like:
INSERT INTO table (..., last_polled_on) VALUES (..., NOW());
Your update looks like:
UPDATE table SET ..., last_polled_on = NOW() WHERE ...;
And your select for the next row to poll looks like:
SELECT ... FROM table ORDER BY last_polled_on LIMIT 1;