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Paste multiple columns together
...he answers of Anthony Damico, Brian Diggs and data_steve on a small sample tbl_df and got the following results.
> data <- data.frame('a' = 1:3,
+ 'b' = c('a','b','c'),
+ 'c' = c('d', 'e', 'f'),
+ 'd' = c('g', 'h', 'i'))
> data &l...
Multiple queries executed in java in single statement
...d in the table.
Sample table and procedure:
mysql> create table tbl_mq( i int not null auto_increment, name varchar(10), primary key (i) );
Query OK, 0 rows affected (0.16 sec)
mysql> delimiter //
mysql> create procedure multi_query()
-> begin
-> select count(*) as n...
How to declare a variable in MySQL?
...ue for same session.
Set @Ids = '';
select
@Ids := concat_ws(',',@Ids,tbl.Id),
tbl.Col1,
...
from mytable tbl;
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How do you find the row count for all your tables in Postgres
...add this for the first option (thanks goes to @a_horse_with_no_name): with tbl as (SELECT table_schema,table_name FROM information_schema.tables where table_name not like 'pg_%' and table_schema in ('public')) select table_schema, table_name, (xpath('/row/c/text()', query_to_xml(format('select c...
How does MySQL process ORDER BY and LIMIT in a query?
...ows to return. The offset of the initial row is 0 (not 1):
SELECT * FROM tbl LIMIT 5,10; # Retrieve rows 6-15
To retrieve all rows from a certain offset up to the end of the result set, you can use some large number for the second parameter. This statement retrieves all rows from the 96th row to...
Dynamically select data frame columns using $ and a character value
...Return the string name of the first name in names that is a column name in tbl
# else null
ChooseCorrectColumnName <- function(tbl, names) {
for(n in names) {
if (n %in% colnames(tbl)) {
return(n)
}
}
return(null)
}
then...
cptcodefieldname = ChooseCorrectColumnName(file, c("CPT...
Need to list all triggers in SQL Server database with table name and table's schema
...n execute the following script.
Select
[tgr].[name] as [trigger name],
[tbl].[name] as [table name]
from sysobjects tgr
join sysobjects tbl
on tgr.parent_obj = tbl.id
WHERE tgr.xtype = 'TR'
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How can you determine how much disk space a particular MySQL table is taking up?
...POWER(1024,pw2),2),' ',SUBSTR(units,pw2*2+1,2)) NDXSIZE,
CONCAT(FORMAT(TBL/POWER(1024,pw3),2),' ',SUBSTR(units,pw3*2+1,2)) TBLSIZE
FROM
(
SELECT DAT,NDX,TBL,IF(px>4,4,px) pw1,IF(py>4,4,py) pw2,IF(pz>4,4,pz) pw3
FROM
(
SELECT data_length DAT,index_length NDX,data_len...
How to randomly select rows in SQL?
... the following query will not get a new random value for each row: update tbl_vouchers set tbl_UsersID = (select top(1) id from tbl_Users order by NEWID()) - edit: I can't get formatting to work in comments :(
– Mir
Dec 10 '15 at 18:35
...
How do I join two SQLite tables in my Android application?
I have an Android project that has a database with two tables: tbl_question and tbl_alternative .
4 Answers
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