Name
UID
Late
Tin
ABC
0
Bob
ABC
0
SELECT * FROM `logs` WHERE Name='Tin' AND Name='Feryal'
This query returns nothing for me and only works when I want one name.
I could use the SELECT * but for this case I would like to call specific names in the query?
For this use In clause.
SELECT * FROM logs WHERE Name IN ('Tin', 'Feryal');
You can also use or clause
SELECT * FROM logs WHERE Name='Tin' OR Name='Feryal'
To add on to Amit Verma's answer.
SELECT * FROM `logs` WHERE Name='Tin' AND Name='Feryal'
Reading that SQL statement out loud, it sounds like this:
I want to select all the rows from logs where the name is equal to Tin AND the name is equal to Feryal.
You can quickly see from that statement, the reason why 0 rows are returned, it's because that is impossible! You cannot have somebody named both Tin and Feryal at the same time unless they are some bizarre super-positional being and the datatype in the table somehow allows for that.
Amit covers the rest.
Related
Is there a way to get a column name from table where all values in this column are the same!
Example! IF i would there would be a such a code it would return answer 'Works'
Table1
ID Name Works
1 Andre Yes
2 John Yes
3 Stewart Yes
I don't know if the columns of the table are known. If not, you could be able to get them by:
desc Table1;
or if you are using higher version of MySQL, you could use:
select column_name from information_schema.columns where table_schema='your_schema' and table_name='Table1';
Then you try the following statement with parameters #column being replaced with the column names retrieved from the above statement:
select count(*) from (select count(*) as c from Table1 as t group by t.#column) as sub;
If the result is 1, the column is what you want. The result means how many distinct values this column has.
I suppose you will have to use a kind of programming language or stored procedure. You are not likely being able to achieve that with one single SQL statement.
I'm not sure if it's possible to run from MySQL itself but you can do this from your scripting engine.
You can run a loop on each column and do a query:
SELECT
COUNT(DISTINCT column_name)
FROM table_name;
And see you get 1 record in the results
I have a mysql table contains lot's of records. my table has a varchar field and a timestamp field. (I have one record for every minute)
I want to select records like this:
1,3,5,7,9,11,...
or 1,4,7,10,13,..
or something like this.
I can get done it using php while function, but it is not a good solution. is there any mysql select parameter to get it exactly from mysql?
p.s: sorry for post title, this is the only title stackoverflow accept it.
select * from table where identity_column %2 <>0 -- to select 1,3,5,7,9...
and for your 2 condition do this !
select * from table where identity_column%3 =1 -- to select 1,4,7,10,13,....
For selecting records like 1,3,5,7,9,11,etc. You can do this:
SELECT *
FROM TableName
WHERE autoIncreamentField % 2
NB: Not necessary to check where clause against 0 or 1. It will select records if where clause returns 1. An example in Fiddle.
For records like 1,4,7,10,13,etc. You can do:
SELECT *
FROM TableName
WHERE (autoIncreamentField % 3)=1
select * from table order by rand()
My query is like this
select 5 from mytable_name;
Then the output is like column name 5 and the value is 5 printing as many max number of rows exists in that table.
Can anybody tell the reason why this query is working like this?
Can anybody tell the reason why this query is working like this?
You are selecting a string literal value '5' for each row in your table:
select 5 from mytable_name;
And this works fine. Because in the SELECT statement you can select:
Column reference,
Literal value like in your case.
Function.
value expression.
Select expression.
As defined by the standard SQL1:
Update:
However, If you have a column with a name is a number like in your case, you have to escape it in order to select the values in it like so:
SELECT `143` FROM Table1;
This will select all the rows in the column 143.
But, this:
SELECT 143 FROM Table1;
Will select the string literal 143 for each row found in the table.
Note that: If possible, try not to name these columns this way, it is recommended and a best practice, not to do this.
SQL Fiddle Demo
Update 2:
Note that, if you select 143 or '143', or even "143" this will select the literal value 143 not the column date. The following are the same:
SELECT 143 FROM Table1;
SELECT '143' FROM Table1;
SELECT "143" FROM Table1;
All these SELECTs won't select the data in the column, They will select the literal value 143 not the column data. See this demo:
Demo
You have to escape the column name with the two:
``
Like this:
SELECT `143` FROM table1;
Not:
SELECT '143' FROM table1'
Like what I did here:
The right Demo
1Image From: SQL Queries for Mere Mortals
from mytable
will select all rows from your table if there is no where condition that shrinks that result. and
select 5
will select the constant number 5 for every record. If you use a column name in the select part then that value will be selected for every record.
The DB engine will name the result 5 because it automatically generates a column name and 5 is the logical name for that.
You want 'SELECT * FROM mytable_name LIMIT 0,5' perhaps?
Since you don't have anything in your where clause, it is selecting all the rows from your table. The fact that you don't select any of the columns is irrelevant - you'll still get a result for each row in the table.
With the command select 5 ... you are viewing a fixed value. Same thing you run the following command: select "test", you will be displaying a fixed string.
Using ... from mytable_name you're looking for all record of this table.
With this we can conclude that for each record in the table mytable_name shows you the fixed value "5".
A bit of background
I'm running mySQL on a mac
I have a few databases setup that have been working okay
I have recently created a new table from a sqlDump from another server.
I am having an issue with new rows that equal = a value that I know exists
e.g. Table setup
id=1 name='dave' - already exists in database
id=2 name='john' - I add a new row
Following are the sql I tried with results...
Select * from tablename where id=1 -- I get the correct Dave result.
Select * from tablename where `name` = 'dave' -- I get the correct Dave result.
Select * from tablename where id=2 -- I get the correct John result.
Select * from tablename where `name` like 'joh%' -- I get the correct John result.
Select * from tablename where `name` = 'john' -- (No result!) eek!
Anyone seen this before? it's in the database but a direct match on the name field is not yielding a result.
Thanks in advance
M
One possibility: there could be a trailing space after 'john' in the name column.
One way to check that:
select `name`,char_length(`name`), char_length('john')
from tablename
where id = 2
An easy way to not have to deal with that problem would be to trim your input (if you don't expect to ever have preceding or trailing white space.
In that case you could have a query like:
Select * from tablename where trim(`name`) = trim('john')
I agree with the comments on your question, that it is most likely a hidden space or something similar. If you include the column definitions so we can check the data that your using with the types we could help more. Remove the entry and and retry with a different name other than john and see if you can replicate the problem.
So I have a data with format like ;1;;2; and then I need to use this number in a query so I thought I'd convert it to 1,2 and use that in a IN condition. In my table, the result should return 2 rows but instead it is returning only 1 row.
My query is like this. The subquery return 1,2 with no problem but only 1 row is retrieve.
select *
from wt_lists
where id IN ((select replace (replace(sendto, ';;',','),';','')
from wt_stats where statsid IN (1)))
But when I try it with this. It returns the correct result, which in my case is 2 rows.
select *
from wt_lists
where id IN (1,2)
What am I missing here?
Comma delimited strings need to be explicitly defined in the query in order to be used in the IN clause - there's countless examples on SO where people need to use dynamic SQL to incorporate user submitted comma delimited strings.
That said, I have a solution using the FIND_IN_SET function:
SELECT DISTINCT wl.*
FROM WT_LISTS wl
JOIN (SELECT REPLACE(REPLACE(ws.sendto, ';;',','),';','') AS ids
FROM WT_STATS ws
WHERE ws.statsid = 1) x ON FIND_IN_SET(wl.id, x.ids) > 0
You are replacing the string:
';1;;2;'
To:
'1,2'
So, you SQL query looks like:
select * from wt_lists where id IN ('1,2') from wt_stats where statsid IN (1)
To use IN clause you need select different values in different rows.
I found this store procedure that does exactly what you need.
http://kedar.nitty-witty.com/blog/mysql-stored-procedure-split-delimited-string-into-rows/
I have not tested, but it is the way.
Obs: Like David said in the comments above, parsing the data in your application is a better way to do this.