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#1071 - Specified key was too long; max key length is 1000 bytes
... was too long; max key length is 3072 bytes' when ran this script:
CREATE TABLE IF NOT EXISTS test_table1 (
column1 varchar(500) NOT NULL,
column2 varchar(500) NOT NULL,
column3 varchar(500) NOT NULL,
column4 varchar(500) NOT NULL,
column5 varchar(500) NOT NULL,
column6 varchar(500) NOT...
How to select rows from a DataFrame based on column values?
... links could be very useful to many of you: pandas.pydata.org/pandas-docs/stable/indexing.html gregreda.com/2013/10/26/working-with-pandas-dataframes
– tremendows
May 27 '14 at 7:32
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How can I access the MySQL command line with XAMPP for Windows?
... .\mysql -u root (use this in powershell ".\" means look for executable or binary in present working directory)
– Timothy L.J. Stewart
Jan 5 '17 at 20:39
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Transpose a data frame
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You can use the transpose function from the data.table library. Simple and fast solution that keeps numeric values as numeric.
library(data.table)
# get data
data("mtcars")
# transpose
t_mtcars <- transpose(mtcars)
# get row and colnames in order
colnames(t_mtc...
Is there type Long in SQLite?
I want to create a table with the column type Long instead of Integer . Is it possible?
7 Answers
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MySQL combine two columns into one column
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Try this, it works for me
select (column1 || ' '|| column2) from table;
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Create Pandas DataFrame from a string
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FYI - pd.read_table() is an equivalent function, just slightly better nomenclature: df = pd.read_table(TESTDATA, sep=";").
– wkzhu
Dec 6 '17 at 23:17
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Laravel Schema onDelete set null
Can't figure out how to set proper onDelete constraint on a table in Laravel. (I'm working with SqLite)
4 Answers
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SQLite - UPSERT *not* INSERT or REPLACE
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Assuming three columns in the table: ID, NAME, ROLE
BAD: This will insert or replace all columns with new values for ID=1:
INSERT OR REPLACE INTO Employee (id, name, role)
VALUES (1, 'John Foo', 'CEO');
BAD: This will insert or replace 2 of the...
Replacing NULL with 0 in a SQL server query
...olumn with something else, use IsNull.
SELECT ISNULL(myColumn, 0 ) FROM myTable
This will put a 0 in myColumn if it is null in the first place.
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