I am a little bit confusing and have no idea which one of these two SELECT statments are correct
SELECT Value FROM visibility WHERE site_info LIKE '%site_is_down%';
OR
SELECT Value FROM visibility WHERE site_info = 'site_is_down';
SInce I run both of these I get same result, but I am interesting which one is correct since Value column is VARCHAR data type OR both of these SELECT are incorect ?
Result set running first SELECT
Value
1. 0
Result set running second SELECT
Value
1. 0
The two statements do not do the same thing.
The first statement filters on rows whose site_infos contain string 'site_is_down'. The surrounding '%' are wildcards. So it would match on something like 'It looks like site_is_down right now'.
The second query, with the equality condition, filters on site_info whose content is exactly 'site_is_dow'.
Everything that the second query is also returned by the first query - but the opposite is not true.
Which statement is "correct" depends on your actual requirement.
If both queries are useful for you, I'd use the second query, as it is the simplest, and runs faster.
Related
I have a database with MANY out-of-date file locations. The difference between the out-of-date file locations and the correct locations is simply the left-side of the address. So, I am attempting to take the left-side off and replace it with the correct string. But, I can't get there because my query is altering the right-side of the address.
This query is made using "vfpoledb."
SELECT RIGHT(LINK,LEN(LINK)-8) ,LEN(LINK)-8,RIGHT(LINK,77),LINK
FROM LINKSTORE
WHERE DOCLBL = "V46145002A"
This query returns the following:
EXP1:
\SHARES\DATA\QMS\QMS DATA\TRACKING FILES\REMOTEENTRIES\V46145 216447
EXP2:
77
EXP3:
\SHARES\DATA\QMS\QMS DATA\TRACKING FILES\REMOTEENTRIES\V46145 216447-002A.PDF
LINK:
\\SERVER\SHARES\DATA\QMS\QMS DATA\TRACKING FILES\REMOTEENTRIES\V46145 216447-002A.PDF
I don't understand why EXP1 and EXP3 are giving different results. EXP3 is what I'm looking for EXP1 to return. If I could get that, I could append the correct left-hand-side and create an update query to fix everything.
Edit:
Even when changing the query to:
SELECT RIGHT(LINK,LEN(LINK)) ,LEN(LINK)-8,RIGHT(LINK,77),LINK
FROM LINKSTORE
WHERE DOCLBL = "V46145002A"
The link still cuts off at the same point, which is odd because expression_3 which still uses Right(), but manually provides the length instead of using Len() does not do this.
Furthermore, it seems that when I run the query to include all results:
SELECT RIGHT(LINK,LEN(LINK)) ,LEN(LINK)-8,RIGHT(LINK,77),LINK
FROM LINKSTORE
WHERE 1=1
All values returned by Exp1 are equal in length even though Exp2 and Link are different in size.
So back to the problem, how can I run a query to replace the left-side with the correct server if I can't separate them out?
OK this is tricky, I did some Foxpro 20 years ago but don't have it to hand.
Your SELECT statement looks OK to me. In the comments under the question Thomas G created this DbFiddle which shows that in a 'normal' dbms, your SELECT statement gives the result you are expecting: https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=37047d2b7efb91aaa029fa0fb98eea24
So the problem must be something FoxPro/dBase specific rather than a problem with your SELECT statement.
Reading up I see people say that with FoxPro always use ALLTRIM() when using RIGHT() or LEN() on table fields because the data gets returned padded with spaces. I don't see how that would cause the exact bug you're seeing but you could try this maybe:
SELECT RIGHT(ALLTRIM(LINK),LEN(ALLTRIM(LINK))-8) ,LEN(ALLTRIM(LINK))-8,RIGHT(ALLTRIM(LINK),77),ALLTRIM(LINK)
FROM LINKSTORE
WHERE DOCLBL = "V46145002A"
edit: OK I got a better idea - are there other rows in your result set?
According to this: https://www.tek-tips.com/viewthread.cfm?qid=1706948 ... when you do SELECT (expr) in FoxPro whatever the length of the expr in the first row becomes that max length for that 'field' and so all subsequent rows get truncated to that length. Makes sense in a crazy 1970s sort of way.
So perhaps you have a row of data above the one we are talking about which comes out at 68 chars long and so every subsequent value gets truncated to that length.
The way around it is to pad your expression results with CAST or PADR:
SELECT PADR(RIGHT(ALLTRIM(LINK),LEN(ALLTRIM(LINK))-8),100),LEN(ALLTRIM(LINK))-8,PADR(RIGHT(ALLTRIM(LINK),77),100),LINK
FROM LINKSTORE
WHERE DOCLBL = "V46145002A"
Or same without the ALLTRIM()
SELECT PADR(RIGHT(LINK,LEN(LINK)-8),100),LEN(LINK)-8,PADR(RIGHT(LINK,77),100),LINK
FROM LINKSTORE
WHERE DOCLBL = "V46145002A"
I want to add a column called "Sweep" that contains bools based on whether the "Result" was a sweep or not. So I want the value in the "Sweep" column to be True if the "Result" is '4-0' or '0-4' and False if it isn't.
This is a part of the table:
I tried this:
ALTER TABLE "NBA_finals_1950-2018"
ADD "Sweep" BOOL;
UPDATE "NBA_finals_1950-2018"
SET "Sweep" = ("Result" = '4-0' OR "Result" = '0-4');
But for some reason, when I run this code...:
SELECT *
FROM "NBA_finals_1950-2018"
ORDER BY "Year";
...only one of the rows (last row) has the value True even though there are other rows where the result is a sweep ('4-0' or '0-4') as shown in the picture below.
I don't know why this is happening but I guess there is something wrong with the UPDATE...SET code. Please help.
Thanks in advance.
NOTE: I am using PostgreSQL 13
This would occur if the strings are not really what they look like -- this is often due to spaces at the beginning or end. Or perhaps to hyphens being different, or other look-alike characters.
You just need to find the right pattern. So so with a select. This returns no values:
select *
from "NBA_finals_1950-2018"
where "Result" in ('4-0', '0-4');
You can try:
where "Result" like '%0-4%' or
"Result" like '%4-0%'
But, this should do what you want:
where "Result" like '%4%' and
"Result" like '%0%'
because the numbers are all single digits.
You can incorporate this into the update statement.
Note: double quotes are a bad idea. I would recommend creating tables and columns without escaping the names.
I am trying to connect a Filemaker DB to Firebird SQL DB in both ways import to FM and export back to Firebird DB.
So far it works using the MBS Plug-in but FM 13 Pro canot handle NULL.
That means that for example Timestamp fields that are empty (NULL) produce a "0" value.
Thats means in Time something like 01.01.1889 00:00:00.
So my idea was to simply ignore fields containing NULL.
But here my poor knowlege stops.
First I thought I can do this with WHERE, but this is ignoring whole records sets:
SELECT * FROM TABLE WHERE FIELD IS NOT NULL
Also I tried to filter it later on like this:
If (IsEmpty (MBS("SQL.GetFieldAsDateTime"; $command; "FIELD") ) = 0 ; MBS("SQL.GetFieldAsDateTime"; $command; "FIELD"))
With no result either.
This is a direct answer to halfbit's suggestion, which is correct but not for this SQL dialect. In a query to provide a replacement value when a field is NULL you need to use COALESCE(x,y). Where if X is null, Y will be used, and if Y is null then the field is NULL. Thats why it is common for me to use it like COALESCE(table.field,'') such that a constant is always outputted if table.field happens to be NULL.
select COALESCE(null,'Hello') as stackoverflow from rdb$database
You can use COALESCE() for more than two arguments, I just used two for conciseness.
I dont know the special SQL dialect, but
SELECT field1, field2, value(field, 0), ...FROM TABLE
should help you:
value gives the first argument, ie, your field if it is NOT NULL or the second argument if it is.
Well basically I would like to be able to use a parameter on iReport with an aggregate function.
If you type "yes" it will show you the values greater than 0, if you type "no" it will show the values that are less than 0. However, the aggregate function first adds up all the values related to an id and then it subtracts the result from another value, the result of that is the one I want to show.
How would I be able to do this? I'm clueless as I don't know how to use it with HAVING.
I don't understand what 'it' refers to in "I don't know how to use it with HAVING." The question will be much clearer with some SQL. But I guess you're looking for this:
SELECT id, sum(values) as the_agg
FROM table1
GROUP BY id
HAVING sum(values) $P!{BiggerOrSmaller} 0
The default value for the parameter BiggerOrSmaller should be like this:
$P{MyParam}.equals("yes") ? ">" : "<"
This assumes you have a parmeter called MyParam which can take the value "yes". Based on that value it sets the parameter BiggerOrSmaller appropriately.
I found a weird problem with MySQL select statement having "IN" in where clause:
I am trying this query:
SELECT ads.*
FROM advertisement_urls ads
WHERE ad_pool_id = 5
AND status = 1
AND ads.id = 23
AND 3 NOT IN (hide_from_publishers)
ORDER BY rank desc
In above SQL hide_from_publishers is a column of advertisement_urls table, with values as comma separated integers, e.g. 4,2 or 2,7,3 etc.
As a result, if hide_from_publishers contains same above two values, it should return only record for "4,2" but it returns both records
Now, if I change the value of hide_for_columns for second set to 3,2,7 and run the query again, it will return single record which is correct output.
Instead of hide_from_publishers if I use direct values there, i.e. (2,7,3) it does recognize and returns single record.
Any thoughts about this strange problem or am I doing something wrong?
There is a difference between the tuple (1, 2, 3) and the string "1, 2, 3". The former is three values, the latter is a single string value that just happens to look like three values to human eyes. As far as the DBMS is concerned, it's still a single value.
If you want more than one value associated with a record, you shouldn't be storing it as a comma-separated value within a single field, you should store it in another table and join it. That way the data remains structured and you can use it as part of a query.
You need to treat the comma-delimited hide_from_publishers column as a string. You can use the LOCATE function to determine if your value exists in the string.
Note that I've added leading and trailing commas to both strings so that a search for "3" doesn't accidentally match "13".
select ads.*
from advertisement_urls ads
where ad_pool_id = 5
and status = 1
and ads.id = 23
and locate(',3,', ','+hide_from_publishers+',') = 0
order by rank desc
You need to split the string of values into separate values. See this SO question...
Can Mysql Split a column?
As well as the supplied example...
http://blog.fedecarg.com/2009/02/22/mysql-split-string-function/
Here is another SO question:
MySQL query finding values in a comma separated string
And the suggested solution:
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_find-in-set