OR shows result, AND doesn't show - sql

I have the following problem, a table as simple as
PERSON:
FNAME LNAME AGE
-----------------
John Carl 22
Rupert Luis 24
If I execute the following T-SQL query:
Select *
from PERSON
WHERE FNAME = 'John' AND LNAME = 'Carl'
It doesn't show any results... and if I place an OR instead of AND it does, to me it makes no sense, but it probably is correct, I just want to understand why so?

The way that you have shown the data, there is a space at the beginning of the last name. I don't know if that is true in the original data, but it is true in the query.
Then strings 'CARL' and ' CARL' are not the same. You can do the comparisons as:
where ltrim(rtrim(firstname)) = 'John' and ltrim(rtrim(lastname)) = 'Carl'
Or you could fix the data:
update person
set lastname = ltrim(rtrim(lastname));
Or, there might be another similar problem, typically caused by:
Hidden characters in the string that don't print (often at the beginning or end).
Characters that look similar but are different, such as zero and capital-O.

You are not doing something wrong with AND OR
As the data appears the AND should return the data
Most likely what you have is data that appears to be the same but is not
Do this to figure out which is missing
Select *
from PERSON
WHERE FNAME = 'John'
Select *
from PERSON
WHERE LNAME = 'Carl'
On the one that returns nothing try
Select *
from PERSON
WHERE LNAME like '%Carl%'

Related

How to search name, (OPTIONAL) second name, surname on SQL?

I am not usually an SQL person but need to find matching name/surnames from a list of people on MSSql. I am trying to find similar names from TABLENAME to match the list of people that I have. The line looks like this:
Select *
from TABLENAME(nolock)
Where SomeRule='04' and RTRIM(Name) +' ' + RTRIM(SecondName) +' '+RTRIM(Surname) in (THE LIST OF PEOPLE HERE)
But this method only gives me the match of people with second names. If someone does not have a second name but their name+surname match, it does not show up. I want to see people who have 100% match of name-second name-surname OR name-surname (if they don't have second name).
Thank you guys in advance
Provided list of people is a table
Select distinct t.*
from TABLENAME t
join [THE LIST OF PEOPLE HERE] lp on SomeRule='04'
and RTRIM(t.Name) = lp.Name
and RTRIM(t.Surname) = lp.Surname
and (t.SecondName is null and pl.SecondName is null or RTRIM(t.SecondName) = lp.SecondName)
Let's look at some rows:
Name
SecondName
Surname
Remark
Your concatenation
'John'
'Thomas'
'Smith'
Person with middle name
'John Thomas Smith'
'John'
''
'Smith'
Person that has no middle name
'John  Smith'
'John'
null
'Smith'
Person with an unknown middle name
null
The person without a middle name cannot be found because of two blanks separating first and last name in your created string. The person of whom we don't know the middle name cannot be found because the concatenated string is null.
You can use CASE WHEN to check this and react accordingly:
select *
from tablename
where somerule = '04'
and
rtrim(name) + ' ' +
case when rtrim(secondname) is null then ''
when rtrim(secondname) = '' then ''
else rtrim(secondname) + ' '
end +
rtrim(surname) in (the list of people here)

Find the names of employees whose name has more than two ‘a’ in it and ends with ‘s’. ORACLE SQL

I'm attempting to select from a table the names of employees whose name has two 'a' in it and end with s. Heres what I have so far
select NAME from CLASS where NAME LIKE '%s'
I know how to find names where they end with s but not sure how to search for names having atleast two 'a'.
Am I missing something, or could you just not just write
select NAME from CLASS where LOWER(NAME) LIKE '%a%a%a%s'
?
This selects every name that has at least three (i.e. more than two) as, and ends with an s.
One option might be
where regexp_count(name, 'a', 1, 'i') = 2
and substr(lower(name), -1) = 's'
number of 'a' letters - starting at position 1, performing case insensitive search ('i') = 2
the last character is 's'
Found a solution:
select NAME from CLASS where NAME LIKE '%s' and REGEXP_COUNT(NAME, 'a') > 2;
Try this:
select NAME from test where regexp_like(NAME,'[a]{2}[a-z]*[s]$');

extracting last name from a name string in ORACLE DB

I am writing a small query to extract all last names from a bunch of Author name database. Names on file will contain first and middle name, or just first name.
Ex: John Smith
John T. Smith
So I cannot search purely by just after the first space... But I know for sure that the lastname should be from the END to the first space from the right side of the string. I don't really care about first name.
This is what I currently have...
select [name], LEFT([name], CHARINDEX(' ', [name] + ' ')-1) as firstName,
SUBSTRING([name], charindex(' ', [name]+' ') + 1, LEN([name])) as lastName
from Author
;
I am quite new to sql, any help is highly appreciated!
Thanks in advance!
EDIT: for those who ever come across this need for help, this line helps:
select substr(t.string,instr(t.string,' ',-1)+1) last_word
For Oracle DB try this :
WITH t AS
(SELECT name AS l FROM <your query>
)
SELECT SUBSTR(l,instr(l,' ',-1)+1,LENGTH(l)) FROM t;
SUBSTRING_INDEX() should work in this case.
select name, SUBSTRING_INDEX(name,' ',-1) as lastName from Author;

Oracle SQL - See if Value Contains Substrings from Three Other Values

I have three columns for a person's name (first middle last) and a column for a user ID.
The purpose of this code is to find persons with a UserID that does not match their name.
The UserID is created by taking the FIRST letter of the first name, the FIRST letter of the middle name and the FULL last name. Mary Jane Smith would have the UserID of MJSmith34. Random numbers are added to the end when there is more than one MJSmith, but this does not matter for what I need.
The code below compares the person's last name in two areas. If they do not match, it means that the person's name has been changed. What I need now is to check the UserID against the most current First Middle Last name to see if the UserID need to be changed (updated). The Pseudocode is what I need, but I am not sure if it can even be done. Please help!!
Select DISTINCT
NL.spriden_id as "STU_ID",
NL.SPRIDEN_LAST_NAME as "Last_Name" ,
NL.SPRIDEN_FIRST_NAME as "First_Name"
FROM SARADAP SA
JOIN SPRIDEN NM -- NM is Name
ON SA.SARADAP_PIDM = NM.SPRIDEN_PIDM
JOIN SPRIDEN NL -- NL is null
ON SA.SARADAP_PIDM = NL.SPRIDEN_PIDM
JOIN IDTABLE ID
ON ST.SOMETABLE_PIDM = ID.IDTABLE_PIDM =
WHERE
NM.SPRIDEN_CHANGE_IND LIKE '%N%'
AND
NL.SPRIDEN_CHANGE_IND IS NULL
AND
NL.SPRIDEN_ACTIVITY_DATE between sysdate - 10 and sysdate
AND
NL.spriden_id LIKE 'A00%'
AND
lower(NL.SPRIDEN_LAST_NAME) <> lower(NM.SPRIDEN_LAST_NAME)
AND
NL.SPRIDEN_ACTIVITY_DATE <> NM.SPRIDEN_ACTIVITY_DATE
Pseudocode -
I know I need something with the POSITION of the characters.
I need help making this pseudocode into real code, please! :)
AND ID.USERID LIKE '%(NL.SPRIDEN_LAST_NAME)%'
AND SUBSTRING (1st CHAR OF ID.USERID) LIKE
SUBSTRING FIRST CHARACTER OF (NL.SPRIDEN_FIRST_NAME)
AND SUBSTRING (2nd char of ID.USERID) LIKE
SUBSTRING FIRST CHAR OF (NL.SPRIDEN_MIDDLE_NAME)
AND ID.USERID LIKE SUBSTR(NL.SPRIDEN_FIRST_NAME, 1, 1)
|| SUBSTR(NL.SPRIDEN_MIDDLE_NAME, 1, 1)
|| NL.SPRIDEN_LAST_NAME || '%'
|| is a concatenation operator
This condition means: check if USERID starts with the first symbol SPRIDEN_FIRST_NAME + the first symbol of SPRIDEN_MIDDLE_NAME + SPRIDEN_LAST_NAME
A slight variation on Multisync's good answer:
AND REGEXP_LIKE(ID.USERID, SUBSTR(NL.SPRIDEN_FIRST_NAME, 1, 1)
|| SUBSTR(NL.SPRIDEN_MIDDLE_NAME, 1, 1)
|| NL.SPRIDEN_LAST_NAME || '[0-9]*$', 'i')
-- ^
-- case insensitive compare
That way you won't have false positive for cases such as James Tiberius Kirk => jtkirkwood and you get case insensitive compare "for free".
The drawback here is I assume you don't have regex special characters as part of the name of your users...
Think about normalizing case too!

sql with <> and substring function

The output of query has to return records where company is not equal to 'CABS' OR substring of company until empty space (eg CABS NUTS).The company name can the CABS, COBS, CABST , CABS NUTS , CAB
SELECT *
FROM records
WHERE UPPER(SUBSTR(company, 0, (INSTR(company,' ')-1))) <> 'CABS'
OR COMPANY <> 'CABS'
But the above query is returing CABS NUTS along with COBS , CAB.
I tried using "LIKE CABS" it looks fine but if the company name is "CAB" it will not return "CABS" and CABS NUTS because of like. So LIKE is completely ruled out.
Can anyone please suggest me.
So you want all records where the first 4 characters of the Company field are not "CABS". Okay.
WHERE left(company, 4) != 'CABS'
SELECT
*
FROM
Records
WHERE
LEFT(Company, 4) <> 'CABS'
AND Company <> 'CABS'
Note: Basic TSQL String Comparison is case-insensitive
Can quite work out which ones you do want returns, but have you considered LIKE 'CABS %'
select * from records where company NOT IN (SELECT company
FROM records
WHERE UPPER(SUBSTR(company, 0, (INSTR(company,' ')-1))) = 'CABS'
OR COMPANY = 'CABS')
I think this will fetch the desired records from the records table
RECORDS:
COMPANY
=====================
CAB
CABST
COBS
First, I think you should use AND instead of OR in your compound condition.
Second, you could simplify the condition this way:
WHERE UPPER(SUBSTR(company, 0, (INSTR(company || ' ',' ') - 1))) <> 'CABS'
That is, the company <> 'CABS' part is not needed in this case.
The problem you are getting comes about because the result of the SUBSTR is null if there is not a space. And thanks to three value logic, the result of some_var <> NULL is NULL, rather than TRUE as you might expect.
And example of this is shown by the query below:
with mytab as (
select 1 as myval from dual union all
select 2 as myval from dual union all
select null as myval from dual
)
select *
from mytab
where myval = 1
union all
select *
from mytab
where myval <> 1
This example will only return two rows rather than three rows that you might expect.
There are several ways to rewrite the condition to make it ignore the null result from the substr function. These are listed below. However, as mentioned by one of the other respondents, the two conditions need to be joined using the AND operator rather than OR.
Firstly, you could explicitly check that the column has a space in it using the set of conditions below:
(INSTR(company,' ') = 0 or
UPPER(SUBSTR(company, 0, (INSTR(company,' ')-1))) <> 'CABS') and
COMPANY <> 'CABS'
Another option would be to use the LNNVL function. This is a function that I only recently found out about. It return TRUE from a condition when the result of the condition provided as the input is FALSE or NULL.
lnnvl(UPPER(SUBSTR(company, 0, (INSTR(company,' ')-1))) = 'CABS') and
COMPANY <> 'CABS'
And another option (which would probably be my preferred option) is to use the REGEXP_LIKE function. This is simple, to the point and easy to read.
WHERE not regexp_like(company, '^CABS( |$)')