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sql - MYSQL output in tree format OR Adding level (Parent-Child)

Below is what I have in my table.

myTable

++++++++++++++++++++
Parent   +  Child
++++++++++++++++++++
  C1     +    G1
  C1     +    G2
  C1     +    G3
  G3     +    D1
  G3     +    D2
  C1     +    G4
  G4     +    D3
  G4     +    D4
  C2     +    G5
  C2     +    G6
  C2     +    G7
  C2     +    G8
 ++++++++++++++++++++

What, I want is as below using MYSQL.

C1
  G1
  G2
  G3
    D1
    D2
  G4
    D3
    D4

C2
  G5
  G6
  G7
  G8

Please let me know if this is possible in MYSQL. The output is something like TREE.

Update 1

If I get new table like below is also fine so that I can use this example.

++++++++++++++++++++++++++++++++++++++++
Parent   +  Child   + PLevel  + CLevel
++++++++++++++++++++++++++++++++++++++++
  C1     +    G1    +   1    +   2
  C1     +    G2    +   1    +   2
  C1     +    G3    +   1    +   2
  G3     +    D1    +   2    +   3
  G3     +    D2    +   2    +   3
  C1     +    G4    +   1    +   2
  G4     +    D3    +   2    +   3
  G4     +    D4    +   2    +   3
  C2     +    G5    +   1    +   2
  C2     +    G6    +   1    +   2
  C2     +    G7    +   1    +   2
  C2     +    G8    +   1    +   2
++++++++++++++++++++++++++++++++++++++++

NOTE : I have started level with 1 (in example I have level starting from 0). If I get this new table with level starting from 0 is also fine.

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1 Answer

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MySQL and RDBMS's in general are not great at this sort of structure. You'll probably have to use client-side recursion to do this.

If the recursion is limited to just three deep, like your example, you can do it with joins, but it's not very scalable for deeper trees.


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