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.
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I have a database with MANY out-of-date file locations. The difference between the out-of-date file locations and the correct locations is simply the left-side of the address.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"
Initial situation
I have a relatively large table (ca. 0.7 Mio records) where an nvarchar field "MediaID" contains largely media IDs in proper hexadecimal notation (as they should).
Within my "sequential" query (each query depends on the output of the query before, this is all in pure T-SQL) I have to convert these hexadecimal values into decimal bigint values in order to do further calculations and filtering on these calculated values for the subsequent queries.
--> So far, no problem. The "sequential" query works fine.
Problem
Unfortunately, some of these Media IDs do contain non-hex characters - most probably because there was some typing errors by the people which have added them or through import errors from the previous business system.
Because of these non-hex chars, the whole query fails (of course) because the conversion hits an error.
For my current purpose, such rows must be skipped/ignored as they are clearly wrong and cannot be used (there are no medias / data carriers in use with the current business system which can have non-hex character IDs).
Manual editing of the data is not an option as there are too many errors and it is not clear with what the data must be replaced.
Challenge
To create a query which only returns records which have valid hex values within the media ID field.
(Unfortunately, my SQL skills are not enough to create the above query. Your help is highly appreciated.)
The relevant section of the larger query looks like this (xxxx is where your help comes in :-))
select
pureMediaID
, mediaID
, CUSTOMERID
,CONTRACT_CUSTOMERID
from
(
select concat('0x', Replace(Ltrim(Replace(mediaID, '0', ' ')), ' ', '0')) AS pureMediaID
--, CUSTOMERID
, *
from M_T_CONTRACT_CUSTOMERS
where mediaID is not null
and mediaID like '0%'
and xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
) as inner1
EDIT: As per request I have added here some good and some bad data:
Good:
4335463357
4335459809
1426427996
4335463509
4335515039
4335465134
4427370396
4335415661
4427369036
4335419089
004BB03433
004e7cf9c6
00BD23133
00EE13D8C1
00CCB5522C
00C46522C
00dbbe3433
Bad:
4564589+
AB6B8BFC.8
7B498DFCnm
DB218DFChb
d<tgfh8CFC
CB9E8AFCzj
B458DFCjhl
rytzju8DFC
BFCtdsjshj
DB9888FCgf
9BC08CFCyx
EB198DFCzj
4B628CFChj
7B2B8DFCgg
After I did upgrade the compatibility level of the SQL instance to SQL2016 (it was below 2012 before) I could use try_convert with same syntax as the original convert function as donPablo has pointed out. With that the query could run fully through and every MediaID which is not a correct hex value gets nicely converted into a null value - really, really nice.
Exactly what I needed.
Unfortunately, the solution of ALICE... didn't work out for me as this was also (strangely) returning records which had the "+" character within them.
Edit: The added comment of Alice... where you create a calculated field like this:
CASE WHEN "KEY" LIKE '%[^0-9A-F]%' THEN 0 ELSE 1 end as xyz
and then filter in the next query like this:
where xyz = 1
works also with SQL Instances with compatibility level < SQL 2012.
Great addition for people which still have to work with older SQL instances.
An option (although not ideal in terms of performance) is to check the characters in the MediaID through a case statement and regular expression
Hexadecimals cannot contain characters other than A-F and numbers between 0 and 9
CASE WHEN MediaID LIKE '%[0-9A-F]%' THEN 1 ELSE 0 END
I would recommend writing a function that can be used to evaluate MediaID first and checks if it is hexadecimal and then running the query for conversion
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.
I am working with a pretty badly designed table. I have a field called optional fields which for some reason has been used as a catch-all for someone who didn't want to create the table correctly.
I need to make a query where I look at this optional_fields value and do a comparison on the fifth value of the string in optional_fields.
The value from this field is something like NN14YN...N
My query would be something like:
SELECT COMPANY_NUMBER
FROM table
WHERE fifth character of OPtional Fields = 'Y'
Looking at the supported string functions in DB2 (according to the documentation for DB2 for Linux UNIX and Windows 9.7.0) it would seem that substr could be used:
SELECT COMPANY_NUMBER
FROM table
WHERE substr(optional_Fields,5,1) = 'Y'
In addition to the great answer from #jpw, if you for some reason need to check multiple positions within the string (which I have unfortunately had to do at one time), you can use an IN, and invert the "normal" order, like so:
...
WHERE 'Y' in (
substr(t.flags_field, 123, 1)
,substr(t.flags_field, 19, 1)
,substr(t.flags_field, 128, 1)
,substr(t.flags_field, 1, 1)
)
Just thought I would share. It surprised me the first time I used it!
I have data following data structure..
_ID _BEGIN _END
7003 99210 99217
7003 10225 10324
7003 111111
I want to look through every _BEGIN and _END and return all rows where the input value is between the range of values including the values themselves (i.e. if 10324 is the input, row 2 would be returned)
I have tried this filter but it does not work..
where #theInput between a._BEGIN and a._END
--THIS WORKS
where convert(char(7),'10400') >= convert(char(7),a._BEGIN)
--BUT ADDING THIS BREAKS AND RETURNS NOTHING
AND convert(char(7),'10400') < convert(char(7),a._END)
Less than < and greater than > operators work on xCHAR data types without any syntactical error, but it may go semantically wrong. Look at examples:
1 - SELECT 'ab' BETWEEN 'aa' AND 'ac' # returns TRUE
2 - SELECT '2' BETWEEN '1' AND '10' # returns FALSE
Character 2 as being stored in a xCHAR type has greater value than 1xxxxx
So you should CAST types here. [Exampled on MySQL - For standard compatibility change UNSIGNED to INTEGER]
WHERE CAST(#theInput as UNSIGNED)
BETWEEN CAST(a._BEGIN as UNSIGNED) AND CAST(a._END as UNSIGNED)
You'd better change the types of columns to avoid ambiguity for later use.
This would be the obvious answer...
SELECT *
FROM <YOUR_TABLE_NAME> a
WHERE #theInput between a._BEGIN and a._END
If the data is string (assuming here as we don't know what DB) You could add this.
Declare #searchArg VARCHAR(30) = CAST(#theInput as VARCHAR(30));
SELECT *
FROM <YOUR_TABLE_NAME> a
WHERE #searchArg between a._BEGIN and a._END
If you care about performance and you've got a lot of data and indexes you won't want to include function calls on the column values.. you could in-line this conversion but this assures that your predicates are Sargable.
SELECT * FROM myTable
WHERE
(CAST(#theInput AS char) >= a._BEGIN AND #theInput < a.END);
I also saw several of the same type of questions:
SQL "between" not inclusive
MySQL "between" clause not inclusive?
When I do queries like this, I usually try one side with the greater/less than on either side and work from there. Maybe that can help. I'm very slow, but I do lots of trial and error.
Or, use Tony's convert.
I supposed you can convert them to anything appropriate for your program, numeric or text.
Also, see here, http://technet.microsoft.com/en-us/library/aa226054%28v=sql.80%29.aspx.
I am not convinced you cannot do your CAST in the SELECT.
Nick, here is a MySQL version from SO, MySQL "between" clause not inclusive?