Related to : Return records WHERE selected table column data is not found in another table column
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| Is there a way to not return the `by` column as the first column in a data.table grouping |
| Databases |
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If I group-by using the by keyword in data.table it
always returns the by column as the first column. Is
there a flag/option to tell it not to do this? Or a clever way of
getting rid of it?
In particular I want to group and then
rbindlist to my original table, so infact the issue could
also be said as - "how to stop it reordering the columns"
For example:
DT = data.table(I = as.numeric(1:6),
N = rnorm(6), L = rep(c("a", "b", "c"), 2))
DT[, list(I =
mean(I), N = mean(N)), by= L]
DT
gives:
> DT[, list(I = mean(I), N = mea
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| mysql query to return table.column where the column is the foreign key of another table |
| Databases |
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I am looking for a MySQL query that will return the table name and
column name of any column that is the foreign key of a specified
table.column. If you consider the tables below:
############### ###################
# Table A # #
Table B #
############### ###################
# id #
str # # id # tbl_A_id #
############### ###################
# 1 # str1 # # 1 # 1 #
###############
###################
Where B.tbl_A_id
is a foreign key referencing A.id.
I realize
the following query will in no way actually work, but it is the b
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| copy data from column 1 in table 1 to column 2 in table 2 and ignoring duplicates |
| Databases |
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I have a table 1 in wordpress as
wp_term_relationships (
object_id bigint(20),
term_taxonomy_id bigint(20),
term_order int(11)
)
and table 2 as
wp_test (
object_id bigint(20),
term_taxonomy_id bigint(20)
)
Now I am trying to update
wp_term_relationships with the values in
wp_test as
update ignore
wp_term_relationships m1
inner join wp_test m2
on
(m1.term_taxonomy_id = m2.term_taxonomy_id)
set m1.object_id =
m2.object_id
However,
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| data updation of a column in sql table based on another column of same table |
| Databases |
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i have 2 table with four & five column in sql
in 1st
table four column like ID - Parant - Position - Assign Id
(ID+Position)
in 2nd table five column like assign ID -
ID - L1- L2- L3
assign id & ID automatic update from
1st table
L1,L2,L3 based on assign id & ID column
i
want a query for L1 column for update data like this procedure
find (ID+Left) in assign Id column and if match with records then
copy record from ID column whose matched in assign Id and paste in L1
column
plz help me
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| Return records WHERE selected table column data is not found in another table column |
| Databases |
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I am having trouble figuring out the WHERE syntax for a
query where I want to return only the records where the data in column
"user_ID" from table user_name is not found in the column
"user_ID" from table user_password. So... Code: SELECT
user_login_password.user_ID, user_name.user_ID FROM user_name,
user_login_password How do I set up my WHERE
statement so that if the same data is in both
"user_name.user_ID" and "user_login_password.use
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| sql script to export table's column data to another table's column |
| Databases |
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Let's say , I have two table with same schema but different data
.Table_A and Table_B . Table_A--------ID(p_key) Number(p_key)
Column3
Column4-----------------------------------------------------ID1
1 AAA BBBID1 2
CCC DDDID2 1 EEE
FFFID2 2 GGG
HHH-Table_B--------ID(p_key) Number(p_key) Column3
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