All,
I'm writing a query that includes a CASE statement which compares two datetime fields. If Date B is > Date A, then I'd like the query to display Date B. However, if Date B is not > Date A, then the user who will be getting the report created by the query wants the column to be blank (in other words, not contain the word 'NULL', not contain a hyphen, not contain a low values date). I've been researching this today but have not come up with a viable solution so thought I'd ask here. This is what I have currently:
CASE
WHEN B.DTE_LNP_LAST > A.DTE_PROC_ACT
THEN B.DTE_LNP_LAST
ELSE ?
END AS "DATE OF DISCONNECT"
If I put NULL where the ? is, then I get a hyphen (-) in my query result. If I omit the Else statement, I also get a hyphen in the query result. ' ' doesn't work at all. Does anyone have any thoughts?
Typically the way nulls are displayed is controlled by the client software used to display query results. If you insist on doing that in SQL, you will need to convert the date to a character string:
CASE
WHEN B.DTE_LNP_LAST > A.DTE_PROC_ACT
THEN VARCHAR_FORMAT(B.DTE_LNP_LAST)
ELSE ''
END AS "DATE OF DISCONNECT"
Replace VARCHAR_FORMAT() with the formatting function available in your DB2 version on your platform, if necessary.
You can use the coalesce function
Coalesce (column, 'text')
If the first value is null, it will be replaced by the second one.
Related
I've got a query pulling data from a table. In one particular field, there are several cases where it is a zero, but I need the four digit location number. Here is where I'm running into a problem. I've got
SELECT REPLACE(locationNbr, '0', '1035') AS LOCATION...
Two issues -
Whoever put the table together made all fields VARCHAR, hence the single quotes.
In the cases where there already is the number 1035, I get 1103535 as the location number because it's replacing the zero in the middle of 1035.
How do I select the locationNbr field and leave it alone if it's anything other than zero (as a VARCHAR), but if it is zero, change it to 1035? Is there a way to somehow use TO_NUMBER within the REPLACE?
SELECT CASE WHEN locationNbr='0' THEN '1035' ELSE locationNbr END AS LOCATION...
REPLACE( string, string_to_replace , replacement_string )
REPLACE looks for a string_to_replace inside a string and replaces it with a replacent_string. That is why you get the undesired behaviour - you are using the wrong function.
CASE WHEN condition THEN result1 ELSE result2 END
CASE checks a condition and if it is true it returns result1 and if it is not it will return result2. This is a simple example, you can write a case statement with more than one condition check.
Don't use replace(). Use case:
(case when locationNbr = '0' then '1035' else locationNbr end)
You can make use of length in Oracle:
select case when length(loacation) = 1 then REPLACE(loacation, '0', '1035') else loacation end as location
from location_test;
I'm using SQL Server and do NOT have write access to the DB. I can only extract.
I am left joining to the nph2 table to see if there are records. If there isn't a record, I just need the field to be blank. To illustrate what I am trying to do, one of the fields is 'Status' and this works fine:
case when lsf2.STARTDATE > lsf.STARTDATE and lsf2.STARTDATE is not NULL then
lsf2.LEGALSTATUS else '' end as 'Status'
The other field is a date field and I can not make anything similar work. Such as:
case when lsf2.STARTDATE > lsf.STARTDATE and lsf2.STARTDATE is not NULL then
nph2.STARTDATE else '' end as 'StartDate'
I keep getting '1900-01-01 00:00:00' or an error.
And I understand why I am getting that. I have tried several ways to convert etc., but nothing works.
Basically if my date case is not met because there is no record that meets it, I still need a row with other data in it, but need the date field to populate with nothing. Any ideas would be great.
You need to either settle for NULL in the results or cast the entire expression to a varchar type. You will not be able to put an empty string into a date column.
coalesce(cast(case when lsf2.STARTDATE > lsf.STARTDATE then nph2.STARTDATE else NULL end as varchar(20)),'') as 'StartDate'
I am trying to generate a hive query which will take multiple numeric column names and check whether it is has numeric values. If the column has numeric values then the output should be (column name,true) else if the field has NULL or some string value the output should be (column name,false)
SELECT distinct (test_nr1,test_nr2) FROM test.abc WHERE (test_nr1,test_nr2) not like '%[^0-9]%';
SELECT distinct test_nr1,test_nr2 from test.abc limit 2;
test_nr1 test_nr2
NULL 81432269
NULL 88868060
the desired output should be :
test_nr1 false
test_nr2 true
Since test_nr1 is a decimal field and it has NULL values, it should output false.
Appreciate valuable suggestions.
You can use cast function. It returns NULL when the value can not not be cast to numeric.
For example:
select case when cast('23ccc' as double) is null then false else true end as IsNumber;
You're trying to use character class pattern matching syntax here, and it doesn't work in every SQL implementation IIRC, however, regexp matching works in most, if not all, SQL implementations.
Considering you're using hive, this should do it:
SELECT ('test_nr1', test_nr1 RLIKE '\d'), ('test_nr2', test_nr2 RLIKE '\d') FROM test.abc;
You should remember that regexp matching is very slow in SQL though.
I am working with a table that contains two versions of stored information. To simplify it, one column contains the old description of a file run while another column contains the updated standard for displaying ran files. It gets more complicated in that the older column can have multiple standards within itself. The table:
Old Column New Column
Desc: LGX/101/rpt null
null Home
Print: LGX/234/rpt null
null Print
null Page
I need to combine the two columns into one, but I also need to delete the "Print: " and "Desc: " string from the beginning of the old column values. Any suggestions? Let me know if/when I'm forgetting something you need to know!
(I am writing in Cache SQL, but I'd just like a general approach to my problem, I can figure out the specifics past that.)
EDIT: the condition is that if substr(oldcol,1,5) = 'desc: ' then substr(oldcol,6)
else if substr(oldcol,1,6) = 'print: ' then substr(oldcol,7) etc. So as to take out the "desc: " and the "print: " to sanitize the data somewhat.
EDIT2: I want to make the table look like this:
Col
LGX/101/rpt
Home
LGX/234/rpt
Print
Page
It's difficult to understand what you are looking for exactly. Does the above represent before/after, or both columns that need combining/merging.
My guess is that COALESCE might be able to help you. It takes a bunch of parameters and returns the first non NULL.
It looks like you're wanting to grab values from new if old is NULL and old if new is null. To do that you can use a case statement in your SQL. I know CASE statements are supported by MySQL, I'm not sure if they'll help you here.
SELECT (CASE WHEN old_col IS NULL THEN new_col ELSE old_col END) as val FROM table_name
This will grab new_col if old_col is NULL, otherwise it will grab old_col.
You can remove the Print: and Desc: by using a combination of CharIndex and Substring functions. Here it goes
SELECT CASE WHEN CHARINDEX(':',COALESCE(OldCol,NewCol)) > 0 THEN
SUBSTRING(COALESCE(OldCol,NewCol),CHARINDEX(':',COALESCE(OldCol,NewCol))+1,8000)
ELSE
COALESCE(OldCol,NewCol)
END AS Newcolvalue
FROM [SchemaName].[TableName]
The Charindex gives the position of the character/string you are searching for.
So you get the position of ":" in the computed column(Coalesce part) and pass that value to the substring function. Then add +1 to the position which indicates the substring function to get the part after the ":". Now you have a string without "Desc:" and "Print:".
Hope this helps.
I need to order a select query using a varchar column, using numerical and text order. The query will be done in a java program, using jdbc over postgresql.
If I use ORDER BY in the select clause I obtain:
1
11
2
abc
However, I need to obtain:
1
2
11
abc
The problem is that the column can also contain text.
This question is similar (but targeted for SQL Server):
How do I sort a VARCHAR column in SQL server that contains words and numbers?
However, the solution proposed did not work with PostgreSQL.
Thanks in advance, regards,
I had the same problem and the following code solves it:
SELECT ...
FROM table
order by
CASE WHEN column < 'A'
THEN lpad(column, size, '0')
ELSE column
END;
The size var is the length of the varchar column, e.g 255 for varying(255).
You can use regular expression to do this kind of thing:
select THECOL from ...
order by
case
when substring(THECOL from '^\d+$') is null then 9999
else cast(THECOL as integer)
end,
THECOL
First you use regular expression to detect whether the content of the column is a number or not. In this case I use '^\d+$' but you can modify it to suit the situation.
If the regexp doesn't match, return a big number so this row will fall to the bottom of the order.
If the regexp matches, convert the string to number and then sort on that.
After this, sort regularly with the column.
I'm not aware of any database having a "natural sort", like some know to exist in PHP. All I've found is various functions:
Natural order sort in Postgres
Comment in the PostgreSQL ORDER BY documentation