I am having a table in phpmyadmin named transaction_details where i am having a column named tr_date whose datatype is char(10) and a sample value is '21-02-2016'.
I want to convert that char to date using the following query ---
SELECT str_to_date('SUBSTR( tr_date, 1, 2 ),SUBSTR( tr_date, 4, 2 ),SUBSTR(tr_date, 7, 4 )','%d,%m,%Y') FROM transaction_details where tr_id=3;
But when i execute the query, it returned me NULL. Kindly help me to resolve the issue.
I doubt you need those single quotes. This might be what you are trying to do:
SELECT str_to_date(CONCAT_WS(',' SUBSTR(tr_date, 1, 2 ),
SUBSTR(tr_date, 4, 2 ),
SUBSTR(tr_date, 7, 4 )
), '%d,%m,%Y')
FROM transaction_details
WHERE tr_id = 3;
But really, the string operations are unnecessary. This is the more reasonable solution:
SELECT str_to_date(tr_date, '%d-%m-%Y')
FROM transaction_details
WHERE tr_id = 3;
Related
I am trying to extract values between 2 indices in a JSON array using mysql JSON_EXTRACT.
SELECT JSON_EXTRACT('[10, 20, 30, 40,50, 60]', '$[1]');
This query will smoothly return 20 as result. But if I want to get all the numbers between, say, 1st and 3rd indices, how do I query it?
I was expecting something like:
SELECT JSON_EXTRACT('[10, 20, 30, 40,50, 60]', '$[1]..$[3]'); // Not the proper syntax
which will return 20,30,40. But not working.
How do I achieve this?
SELECT JSON_EXTRACT('[10, 20, 30, 40,50, 60]', CONCAT('$[', idx, ']'))
FROM ( SELECT 1 idx UNION SELECT 2 UNION SELECT 3 ) src;
Of course the indices range can be provided as list/range and converted to rowset in CTE/subquery.
I am working with Codeigniter and its Query Builder class where I have a table with IDs and names.
Those names look like 1234_1a or 2345_2a where 1a can be 1b or 2a,2b,3a... and so on.
Now I want to count all these "1234" and "2345" but write them as one type.
So far I tried with:
$this->db->like('names', '1a', 'before');
$this->db->or_like('names', '1b', 'before');
return $this->db->count_all_results('table');
But the problem:
What if there is 3456_2a but no 3456_1a, than it doesn't work anymore...
id name
2 1212_1a
3 1243_1a
7 3142_1a
24 1243_2a
30 3142_2b
80 2315_2b
136 1243_3b
512 8562_1a
This is how I would like it:
Result:
name count
1212 1
1243 1
3142 1
2315 1
8562 1
If we always want to return a count value of 1, when the count of the number of rows in more than 1 ... then we aren't really returning a count.
And what is the pattern of the names... do they end with a digit and a letter, or is that underscore character important too?
What is to be done with name values such as 12345a or 5678_b2 or 11_22_3b? How are those to be handled?
Seems to me like we want to use a SQL query like this:
SELECT SUBSTRING_INDEX(t.name,'_',1) AS `foo`
, 1 AS `count`
FROM (
SELECT 2 AS `id`, '1212_1a' AS `name`
UNION ALL SELECT 3, '1243_1a'
UNION ALL SELECT 7, '3142_1a'
UNION ALL SELECT 24, '1243_2a'
UNION ALL SELECT 30, '3142_2b'
UNION ALL SELECT 80, '2315_2b'
UNION ALL SELECT 136, '1243_3b'
UNION ALL SELECT 512, '8562_1a'
) t
GROUP BY `foo`
ORDER BY `foo`
The inline view (derived table) is in the query for testing. Replace that with the table reference:
SELECT SUBSTRING_INDEX(t.name,'_',1) AS `foo`
, 1 AS `count`
FROM mytable t
GROUP BY `foo`
ORDER BY `foo`
The expression for foo may need to be adjusted, to get desirable behavior with values that don't follow the regular pattern. Consider name values with no underscore, with more than one underscore, with endings other than a digit. We could also include a WHERE clause to exclude rows that don't follow the pattern,
WHERE t.name REGEXP '_[0-9][a-z]$'
(only name values that end with underscore, digit, lowercase letter).
Without a tested SQL query, I wouldn't know what to implement in CodeIgniter Query Builder.
I want to know how we can find of length of Numeric field in sql. What will be the command / Query so that we can find length of perticular field in table.
E.g.:
For below table:
Column1 Column2
1 1111
2 11
3 44444
4 11
5 111
From above example I want to see Record/fields in column "column2" which has numeric length '2'.
What query should I execute to achieve this?
You can also use the POWER function and < and >= to maintain SARGability
WITH tbl (column1, column2) AS(
SELECT 1, 1111 UNION ALL
SELECT 2, 11 UNION ALL
SELECT 3, 44444 UNION ALL
SELECT 4, 11 UNION ALL
SELECT 5, 111
)
SELECT *
FROM tbl
WHERE
column2 < POWER(10, 2)
AND column2 >= POWER(10, 1)
Use LEN function
select *
from table
where len(column2) = 2
This will not work when you want to include data like '0.2' or similar values
You can't as stated here
Length and digits are both properties of a physical representation of a number in a specific base, i.e. a String.
So you have to convert numeric field to varchar/char first then find the length as follows:
SQL Server:
select *
from table
where len(CONVERT (varchar(10), colunm2 )) = 2
MySQL:
select *
from table
where length(convert(column2,char)) = 2
Hey guys i have did some coding in mysql to add a new line value to a row..
SELECT
babe
FROM
(SELECT
concat_ws(' ', 'assword \n') AS babe,
) test;
When i did like this i get an output like
BABE
assword name
What i need is an output like
BABE
assword
name(this would be below assword)
Is there any mysql functions to do this ??...or can i UPDATE the row ??..
I am a newbie in mysql. Hope you guys can help me out..Thanks in advance..
The statement includes a newline character in the babe column. You can confirm this by using the HEX() function to view the character encodings.
For example:
SELECT HEX(t.babe)
FROM ( SELECT CONCAT_WS(' ', 'assword \n') AS babe ) t
On my system, that Will output:
617373776F7264200A
It's easy enough to understand what was returned
a s s w o r d \n
61 73 73 77 6F 72 64 20 0A
(In the original query, there's an extraneous comma that will prevent the statement from running. Perhaps there was another expression in the SELECT list of the inline view, and that was returning the 'name' value that's shown in the example output. But we don't see any reference to that in the outer query.
It's not clear why you need the newline character. If you want to return:
BABE
-----------
asssword
name
That looks like two separate rows to me. But it's valid (but peculiar) to do this:
SELECT t.babe
FROM ( SELECT CONCAT_WS(' ', 'assword \nname') AS babe ) t
FOLLOWUP
Q: i just wanted to know how to add a new row below the assword ..if u know please edit the answer
It's not clear what result you are trying to achieve. The specification, divorced from the context of a use-case, is just bizarre.
A: If I had a need to return two rows: one row with the literal 'assword' and another row "below" it with the literal 'name', I could do this:
( SELECT 'assword' AS some_string )
UNION ALL
( SELECT 'name' AS some_string )
ORDER BY some_string
In this particular case, we can get the ordering we need by a simple reference to the column in the ORDER BY clause.
In the more general case, when there isn't a convenient expression for the ORDER BY clause, I would add an additional column, and perform a SELECT on the resultset from the UNION ALL operation. In this example, that "extra" column is named seq:
SELECT t.some_string
FROM ( SELECT 'assword' AS some_string, 1 AS seq
UNION ALL SELECT 'name', 2
)
ORDER BY t.seq
As another example:
( SELECT 'do' AS tone, 1 AS seq )
UNION ALL ( SELECT 're', 2 )
UNION ALL ( SELECT 'mi', 3 )
UNION ALL ( SELECT 'fa', 4 )
ORDER BY seq
I'd only need to add an outer SELECT if I needed a projection operation (for example, to remove the seq column from the returned resultset.
SELECT t.tone
FROM ( SELECT 'do' AS tone, 1 AS seq
UNION ALL SELECT 're', 2
UNION ALL SELECT 'mi', 3
UNION ALL SELECT 'fa', 4
)
ORDER BY t.seq
For experimental purposes only.
I would like to build a query but not querying data extracted for any table but querying data provided in the query it self. Like:
select numbers.* from (1, 2, 3) as numbers;
or
select numbers.* from (field1 = 1, field2 = 2, field3 = 3) as numbers;
so I can do things like
select
numbers.*
from (field1 = 1, field2 = 2, field3 = 3) as numbers
where numbers.field1 > 1;
If the solution is specific for a database engine could be interesting too.
If you wanted the values to be on separate rows instead of three fields of the same row, the method is the same, just one row per value linked with a union all.
select *
from(
select 1 as FieldName union all
select 2 union all
select 3 union all
select 4 union all -- we could continue this for a long time
select 5 -- the end
) as x;
select numbers.*
from(
select 1 ,2, 3
union select 3, 4, 5
union select 6, 7, 8
union select 9, 10, 11 -- we could continue this for a long time
union select 12, 13, 14 -- the end
) as numbers;
This works with MySQL and Postgres (and most others as well).
[Edit] Use union all rather than just union as you do not need to remove duplicates from a list of constants. Give the field(s) in the first select a meaningful name. Otherwise, you can't specify a specific field later on: where x.FieldName = 3.
If you don't provide meaningful names for the fields (as in the second example), the system (at least MySQL where this was tested) will assign the name "1" for the first field, "2" as the second and so on. So, if you want to specify one of the fields, you have to write expressions like this:
where numbers.1 = 3
Use the values row constructor:
select *
from (values (1),(2),(3)) as numbers(nr);
or using a CTE.
with numbers (nr) as (
values (1),(2),(3)
)
select *
from numbers
where nr > 2;
Edit: I just noticed that you also taggeg your question with mysql: the above will not work with MySQL, only with Postgres (and a few other DBMS)
You can use a subquery without table like so:
SELECT
numbers.*
FROM (
SELECT
1 AS a,
2 AS b,
3 AS c
UNION
SELECT
4,
5,
6
) AS numbers
WHERE
numbers.a > 1
If you like queries to always have a table referenced there is a Psuedo table that always has 1 row and no columns called DUAL, you can use it like so:
SELECT
numbers.*
FROM (
SELECT
1 AS a,
2 AS b,
3 AS c
FROM
DUAL
UNION
SELECT
4,
5,
6
FROM
DUAL
) AS numbers
WHERE
numbers.a > 1