MySQL Create Tables Based On Values From A Different Table - php

Question

What is the proper way to automatically create new tables based on values in another table? For instance, If table A has a column named city that contains different city values then I would need to create a new table based on each different city. Then all records with the respective city needs to be inserted into it's respective table. Also, if the city contains a space in the name it needs to be replaced with a an underscore. How could the same be done in MySQL?
In MS ACCESS I could accomplish this by:
Using A Select And Replace Query Named SELREP
SELECT table_A.column1, table_A.column2, table_A.city, Replace([city]," ","_") AS table_name_column FROM table_A;
Create a Public Function MakeTableCity
Public Function MakeTableCity()
DoCmd.SetWarnings False
Dim db As Database
Set db = Application.CurrentDb
Dim distinctValues As DAO.Recordset
Set distinctValues = db.OpenRecordset("SELECT table_name_column FROM SELREP GROUP BY table_name_column", dbOpenSnapshot)
Do Until distinctValues.EOF
DoCmd.RunSQL "SELECT * INTO " & distinctValues("table_name_column") & " FROM SELREP WHERE table_name_column ='" & distinctValues("table_name_column") & "'"
distinctValues.MoveNext
Loop
DoCmd.SetWarnings True
Set distinctValues = Nothing
Set db = Nothing
End Function

Answer 1

If you are planning to create a new
table city with data about cities,
meaning one row for every city, then
go ahead and read the answer.
If , on the other hand, you are
planning to make a new table for
every city, with identical columns,
then your plan is very bad design.
Read about normalization first.
First alternative is to create a table named city with fields that you want. Example:
CREATE TABLE city
( id INT auto_increment PRIMARY KEY
, name VARCHAR(50) NOT NULL
, population INT
, state CHAR(2)
) ;
Then copy the different city names into it with:
INSERT INTO city (name)
( SELECT DINSTINCT city --- change "city" into REPLACE(city, ' ', '_')
FROM table_A --- for the small changes you want
) ;
Then, update the other fields (population, state, etc).
If no two cities have same name, the JOINs between the two tables can then be done using ON table_A.city = city.name
If not, (and better anyway as the Primary Key of city will be smaller), you may ALTER the structure of table table_A by adding a field cityid and dropping the city field. Then the JOINs between the two tables will be done using ON table_A.cityid = city.id
Second option is to directly create table city with:
CREATE TABLE city AS
( SELECT DINSTINCT city AS name --- change "city" into REPLACE(city, ' ', '_')
FROM table_A --- for the small changes you want
) ;
and then alter the table defining Primary Key, adding (population, state, etc).