Import data

Import someone else's data.

In this example you are shown how to make a mimic which essentially makes a copy of the database table so it can be freely edited

and then the newly fresh one when finished can be used to replace the out of date existing table.

Table 1 and 2 show the two separate tables and table 3 displays the results that should be inside the mimic in this example.

Table 1

id	parkingSpace
E01	F8
E02	G22
E03	F7

Table 2

id	name	phone
E01	Harpo	2753
E02	Zeppo	2754
E03	Groucho	2755

Table 3

id	name	phone	parkingSpace
E01	Harpo	2753	F8
E02	Zeppo	2754	G22
E03	Groucho	2755	F7

schema:scott

DROP TABLE employeeParking;
DROP TABLE employeeCopy;
DROP VIEW mimic;

 CREATE TABLE employeeParking(
  id TEXT,
  parkingSpace TEXT );
INSERT INTO employeeParking VALUES ('E01','F8');
INSERT INTO employeeParking VALUES ('E02','G22');
INSERT INTO employeeParking VALUES ('E03','F7');
CREATE TABLE employeeCopy (
  id TEXT,
  name VARCHAR(20),
  phone INTEGER );
INSERT INTO employeeCopy VALUES ('E01','Harpo',2753);
INSERT INTO employeeCopy VALUES ('E02','Zeppo',2754);
INSERT INTO employeeCopy VALUES ('E03','Groucho',2755);

To allow data to be imported into your system a mimic of your system can be made and then all that needs to be done is the rows from the old copy have to be deleted and then the table can be refilled with the fresh imported copy.

This method is not completely ideal but is efficient as a temporary measure until an up to date version of the table is made.

CREATE VIEW mimic AS
     SELECT employeeParking.id, COALESCE(name, employeeParking.id) AS name,
     COALESCE(phone, 'Not Available') AS phone, parkingSpace
       FROM employeeParking LEFT OUTER JOIN
employeeCopy ON (employeeParking.id = employeeCopy.id);
       SELECT * FROM mimic;

SQL HACKS

Hack 10 Converting subqueries into joins

Hack 11 Converting aggregate subqueries into joins

Hack 14 Generate Combinations

Hack 16 Search for a String across columns

Hack 24 Multiply Across a Result Set

Hack 25 Keep a running total

Hack 25.5 Splitting and combining columns

Hack 26 Include the rows your JOIN forgot

Hack 30 Calculate the maximum/minimum of two fields

Hack 33 Get values and subtotals in one shot

Hack 50 Combine tables containing different data

Hack 51/52 Display rows as columns

Hack 55 Import Someone Else's Data

Hack 62 Issue Queries Without Using a Table

Hack 63 Generate rows without tables

Hack 70 Combine your queries

Hack 72 Extract a subset of the results

Hack 78 Break it down by Range

Hack 88 Test two values from a subquery

Hack 98 Find and stop long running queries

Hack 100 Run SQL from a Web Page