What is the equivalent of:
SELECT 0 as foo;
but for strings, is it:
SELECT '' as bar;
?
For more context, this is for a UNION ALL query
[edit]
SELECT NULL is what I was looking for.
In the top query I was doing: SELECT COUNT(DISTINCT(bar)),
But empty strings counted as a distinct char, NULL doesn't.
If you want an "equivalent" of SELECT 0 in string form, then it would be SELECT '0'::int.
If you are looking for a non-null string to represent 'no data,' SELECT '' AS something would suffice
When you call UNION ALL, the expectation is that the columns would align and the data sets would be concatenated along their column orders. Since you want to UNION ALL an integer and char, you will get an error:
edb=# select 0 as something union all select '' as something;
ERROR: invalid input syntax for type integer: ""
LINE 1: select 0 as something union all select '' as something;
^
Therefore, in order to UNION ALL, you'll want to cast your 0 as a char:
edb=# select 0::char as something union all select '' as something;
something
-----------
0
(2 rows)
Caveat
I'm not sure if this is really what you want to do, but if you're looking to UNION ALL the two sets, that's how you'd do it. However, there's a chance this would open up a can of worms -- is '' going to be considered equivalent to 0? And what will you do with non-zero values? Will you still cast those integers into strings? I think you'll need to think through those implications and try to find a way to sanitize your data.
In general, it might be better to work with NULL values if your design allows for it
I need to display the whole number in a field if it starts with "AB" otherwise do not show/display the number.
Your question is missing code of how you display this (since you wrote you need to display it to the field) so i can't answer you with actual code but here is solution.
If you want to select only rows which column1 starts with AB then use LIKE function. So condition at selecting command is Select * from yourtable where column1 LIKE 'AB%'
If you already selected and displayed data, let's say in datagridview, and you want to fill textbox with string that contains AB then you would go through all rows at specific column and look for it with string.Contains("AB");
So basically you put this command in foreach loop and you have it.
I was wrong. You can use a LIKE, just not in the WHERE clause.
;WITH testdata AS (
SELECT 'aw12354' AS val UNION ALL
SELECT 'a12b344' UNION ALL
SELECT 'AB11111' UNION ALL
SELECT '11AB111' UNION ALL
SELECT '11111AB' UNION ALL
SELECT 'ab22222'
)
SELECT
CASE WHEN val LIKE 'AB%' THEN val ELSE NULL END AS valFull
, CASE WHEN val LIKE 'AB%' THEN SUBSTRING(val,3,len(val)) ELSE NULL END AS valNums
FROM testdata
;
You can also use CLR to build a regex solution, but that is a LOT more involved.
SUBBIS
SUBB1D
SUBBD3
SUBB12
In above values, how can I check the last two digits (IS, 1D, D3, 12) are numbers using a sql code?
Do you mean to fetch those values? You can do that with like:
where column like '%[0-9][0-9]'
If you need to ensure that the values always end with 2 numbers, you can do it with similar check constraint.
To check the last two digits are numbers in column, you can use the following script.
... WHERE ISNUMERIC(RIGHT(your_column,2)) = 1
Here RIGHT(your_column,2) will return the last two digits from the string.
or
SELECT ISNUMERIC(RIGHT(your_column,2))
will return 1 (if its number) otherwise 0
You can do it this way:
SELECT MyId,
ISNUMERIC(RIGHT(MyColumn,2)) -- your column to check last 2 (if numeric)
FROM (
----- replace with your table
SELECT 1 MyId,'SUBBIS' MyColumn UNION SELECT 2,'SUBB1D' UNION
SELECT 3,'SUBBD3' UNION SELECT 4,'SUBB12'
----- replace with your table
) A
Hope it helps. :)
You can use like and _ "underscore" to get last one digits record columName
SELECT columName FROM sub WHERE columName LIKE "SUBB__" ;
Record :
columName
SUBBIS
SUBB1D
SUBBD3
SUBB12
SUBBBA
I am trying to locate some problematic records in a very large Oracle table. The column should contain all numeric data even though it is a varchar2 column. I need to find the records which don't contain numeric data (The to_number(col_name) function throws an error when I try to call it on this column).
I was thinking you could use a regexp_like condition and use the regular expression to find any non-numerics. I hope this might help?!
SELECT * FROM table_with_column_to_search WHERE REGEXP_LIKE(varchar_col_with_non_numerics, '[^0-9]+');
To get an indicator:
DECODE( TRANSLATE(your_number,' 0123456789',' ')
e.g.
SQL> select DECODE( TRANSLATE('12345zzz_not_numberee',' 0123456789',' '), NULL, 'number','contains char')
2 from dual
3 /
"contains char"
and
SQL> select DECODE( TRANSLATE('12345',' 0123456789',' '), NULL, 'number','contains char')
2 from dual
3 /
"number"
and
SQL> select DECODE( TRANSLATE('123405',' 0123456789',' '), NULL, 'number','contains char')
2 from dual
3 /
"number"
Oracle 11g has regular expressions so you could use this to get the actual number:
SQL> SELECT colA
2 FROM t1
3 WHERE REGEXP_LIKE(colA, '[[:digit:]]');
COL1
----------
47845
48543
12
...
If there is a non-numeric value like '23g' it will just be ignored.
In contrast to SGB's answer, I prefer doing the regexp defining the actual format of my data and negating that. This allows me to define values like $DDD,DDD,DDD.DD
In the OPs simple scenario, it would look like
SELECT *
FROM table_with_column_to_search
WHERE NOT REGEXP_LIKE(varchar_col_with_non_numerics, '^[0-9]+$');
which finds all non-positive integers. If you wau accept negatiuve integers also, it's an easy change, just add an optional leading minus.
SELECT *
FROM table_with_column_to_search
WHERE NOT REGEXP_LIKE(varchar_col_with_non_numerics, '^-?[0-9]+$');
accepting floating points...
SELECT *
FROM table_with_column_to_search
WHERE NOT REGEXP_LIKE(varchar_col_with_non_numerics, '^-?[0-9]+(\.[0-9]+)?$');
Same goes further with any format. Basically, you will generally already have the formats to validate input data, so when you will desire to find data that does not match that format ... it's simpler to negate that format than come up with another one; which in case of SGB's approach would be a bit tricky to do if you want more than just positive integers.
Use this
SELECT *
FROM TableToSearch
WHERE NOT REGEXP_LIKE(ColumnToSearch, '^-?[0-9]+(\.[0-9]+)?$');
After doing some testing, i came up with this solution, let me know in case it helps.
Add this below 2 conditions in your query and it will find the records which don't contain numeric data
and REGEXP_LIKE(<column_name>, '\D') -- this selects non numeric data
and not REGEXP_LIKE(column_name,'^[-]{1}\d{1}') -- this filters out negative(-) values
Starting with Oracle 12.2 the function to_number has an option ON CONVERSION ERROR clause, that can catch the exception and provide default value.
This can be used for the test of number values. Simple set NULL when the conversion fails and filer all not NULL values.
Example
with num as (
select '123' vc_col from dual union all
select '1,23' from dual union all
select 'RV12P2000' from dual union all
select null from dual)
select
vc_col
from num
where /* filter numbers */
vc_col is not null and
to_number(vc_col DEFAULT NULL ON CONVERSION ERROR) is not null
;
VC_COL
---------
123
1,23
From http://www.dba-oracle.com/t_isnumeric.htm
LENGTH(TRIM(TRANSLATE(, ' +-.0123456789', ' '))) is null
If there is anything left in the string after the TRIM it must be non-numeric characters.
I've found this useful:
select translate('your string','_0123456789','_') from dual
If the result is NULL, it's numeric (ignoring floating point numbers.)
However, I'm a bit baffled why the underscore is needed. Without it the following also returns null:
select translate('s123','0123456789', '') from dual
There is also one of my favorite tricks - not perfect if the string contains stuff like "*" or "#":
SELECT 'is a number' FROM dual WHERE UPPER('123') = LOWER('123')
After doing some testing, building upon the suggestions in the previous answers, there seem to be two usable solutions.
Method 1 is fastest, but less powerful in terms of matching more complex patterns.
Method 2 is more flexible, but slower.
Method 1 - fastest
I've tested this method on a table with 1 million rows.
It seems to be 3.8 times faster than the regex solutions.
The 0-replacement solves the issue that 0 is mapped to a space, and does not seem to slow down the query.
SELECT *
FROM <table>
WHERE TRANSLATE(replace(<char_column>,'0',''),'0123456789',' ') IS NOT NULL;
Method 2 - slower, but more flexible
I've compared the speed of putting the negation inside or outside the regex statement. Both are equally slower than the translate-solution. As a result, #ciuly's approach seems most sensible when using regex.
SELECT *
FROM <table>
WHERE NOT REGEXP_LIKE(<char_column>, '^[0-9]+$');
You can use this one check:
create or replace function to_n(c varchar2) return number is
begin return to_number(c);
exception when others then return -123456;
end;
select id, n from t where to_n(n) = -123456;
I tray order by with problematic column and i find rows with column.
SELECT
D.UNIT_CODE,
D.CUATM,
D.CAPITOL,
D.RIND,
D.COL1 AS COL1
FROM
VW_DATA_ALL_GC D
WHERE
(D.PERIOADA IN (:pPERIOADA)) AND
(D.FORM = 62)
AND D.COL1 IS NOT NULL
-- AND REGEXP_LIKE (D.COL1, '\[\[:alpha:\]\]')
-- AND REGEXP_LIKE(D.COL1, '\[\[:digit:\]\]')
--AND REGEXP_LIKE(TO_CHAR(D.COL1), '\[^0-9\]+')
GROUP BY
D.UNIT_CODE,
D.CUATM,
D.CAPITOL,
D.RIND ,
D.COL1
ORDER BY
D.COL1
I'm trying to pass a null value as something else in my db and it seems to work without a Where clause like so
select NVL(column1, '0') column1 from table1
produces this
0 test1
0 test2
1 test3
But when I add the where clause like so
select NVL(column1, '0') column1 from table1 where column1 <=1
it produces this
1 test3
But now if I add the following to the query it works
select NVL(column1, '0') column1
from table1
where NVL(column1, '0') <=1
But it seems like a long way round to get the value to show correctly with a Where clause
Any ideas what i'm doing wrong?
Thanks in advance
You cannot refer to an alias defined in the SELECT list from the WHERE clause. So if you apply the NVL function in the SELECT list, you'd need the same function call in the WHERE clause (as you've demonstrated) or you would need to apply the function in an inline view
SELECT column1
FROM (SELECT nvl(column1, 0) column1
FROM table1)
WHERE column1 <= 1
Note that for general sanity, if COLUMN1 is a NUMBER, the second parameter to NVL should also be a NUMBER. Otherwise, you're going to do implicit conversions and your comparison operations may end up using string comparison semantics rather than numeric comparison semantics. Since the string '12' is less than the string '2', that can lead to unexpected results.
you have shown the correct way.
an alternative would be to say
OR column IS NULL