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Cannot simply use PostgreSQL table name (“relation does not exist”)
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In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to th...
Delete duplicate rows from small table
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DELETE FROM dupes a
WHERE a.ctid <> (SELECT min(b.ctid)
FROM dupes b
WHERE a.key = b.key);
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Save PL/pgSQL output from PostgreSQL to a CSV file
...e or automate, you can use Postgresql's built in COPY command. e.g.
Copy (Select * From foo) To '/tmp/test.csv' With CSV DELIMITER ',' HEADER;
This approach runs entirely on the remote server - it can't write to your local PC. It also needs to be run as a Postgres "superuser" (normally called "ro...
How can I get the list of a columns in a table for a SQLite database?
...(first_name varchar, last_name varchar, email_address varchar);
sqlite> select * from sqlite_master;
table|people|people|2|CREATE TABLE people (first_name varchar, last_name varchar, email_address varchar)
To get column information you can use the pragma table_info(table_name) statement:
sqlit...
Selecting a row of pandas series/dataframe by integer index
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The primary purpose of the DataFrame indexing operator, [] is to select columns.
When the indexing operator is passed a string or integer, it attempts to find a column with that particular name and return it as a Series.
So, in the question above: df[2] searches for a column name matchin...
MySQL combine two columns into one column
...does not start with a digit, then the converted value is 0.
So try this:
select concat(column1, column2)
Two ways to add a space:
select concat(column1, ' ', column2)
select concat_ws(' ', column1, column2)
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Android - Pulling SQlite database android device
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Yes, this is because the / is as special string char. // in your "//" will result in /.
– KarlKarlsom
Apr 4 '12 at 14:36
4
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How to create a GUID/UUID in Python
...UUID with the dashes included, while uuid4().hex returns "The UUID as a 32-character hexadecimal string"
– stuartd
Jan 30 '18 at 10:08
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What is this: [Ljava.lang.Object;?
... name consists of the name of the element type preceded by one or more '[' characters representing the depth of the array nesting.
The encoding of element type names is as follows:
Element Type Encoding
boolean Z
byte B
char C
double D...
How can I get column names from a table in Oracle?
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You can query the USER_TAB_COLUMNS table for table column metadata.
SELECT table_name, column_name, data_type, data_length
FROM USER_TAB_COLUMNS
WHERE table_name = 'MYTABLE'
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