mysql - column value refer to same table column

lockmaey · #1 (**permalink**) 06-23-12, 11:58

based on title, can it be done with mysql? dont no specific keyword to search on google

for example
i got column a, column b,

column a has it value, and column b, it value refer to column a.

can be it done?

(sorry for my english)

tonkuma · #2 (**permalink**) 06-23-12, 13:05

Please publish sample data and expected result from the sample data.

Like this way...

Source Table:

Code:

my_table looks like...
column_a
----------
abc
12345
x
06/23/2012
80.87

Note: I don't know what data in your table.
So, I showed some data types in the column which might be not compatible each oher.
Actually, the data wouldn' t be mixed such way.

Expeced result from the data:

Code:

column_a   | column_b
-----------+----------
abc        | ???
12345      | ???
x          | ???
06/23/2012 | ???
80.87      | ???

I'm sorry, if I missed the point.

lockmaey · #3 (**permalink**) 06-23-12, 13:20

Quote:

Originally Posted by tonkuma;6557864
Expeced result from the data:
[CODE

column_a | column_b
-----------+----------
abc | ???
12345 | ???
x | ???
06/23/2012 | ???
80.87 | ???
[/CODE]

take your table..lets say

value in column a is 'abc', then the value in column b just based on column a,
that mean also 'abc' (automatically)

Code:

column_a   | column_b
-----------+----------
abc        | abc (<--this value based on value on column a)

it is posibble?

tonkuma · #4 (**permalink**) 06-23-12, 13:58

So, why not

Code:

SELEC column_a
    , column_a AS column_b
 FOM  ...
...

?

lockmaey · #5 (**permalink**) 06-23-12, 14:01

Quote:

Originally Posted by tonkuma

So, why not

Code:

SELEC column_a
    , column_a AS column_b
 FOM  ...
...

?

thx,
but i dont want the select statement. i want to create column.

lockmaey · #6 (**permalink**) 06-23-12, 17:15

nvm.. already find the solution.
i learnt that we cannot create it..
using trigger instead

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