Is it possible to link the public key for every bitcoin address in your database?
If I can get the data I can add it. I'm no expert on this, can I use anything from
inputs (maybe spending_signature_hex?) to get this data?
Yes, spending signature hash contains the public key.
As the example from your blockchair_bitcoin_inputs_20110313.tsv.gz:
1) In case of pubkey (column 'type'), the public key is exactly the value of spending signature. The public key was recorded in blockchain in early dates. So, all the early coin base transactions contains the public key.
block id: 112995
transaction_hash: 523f57581390203da2aef169b543fc1ddcd84be6dd35cfb248228b0912dc97e3
public key: 483045022100a66be0435ed532f7a065073e2549f6cb13a546efc7f55d49072f5038d0764df502206f426bff777dd44ccbab703541a38d8ff86ae09e350862c8fb9cb2b0dd79c5e801
2) For other transactions in your example the public key is part of the hex spending signature. That signature contains DER and public key.
transaction hash: d9ff0a82399ae55ab95093020ed6f17bab80697dcafe74d264900cdd56f8c0aa
48304502200a30a8634f41dbd92c007f937f6b0f220cc1f5a321252cc459092e45b1c53778022100caace1a19e1d195e8510ac290c13863f4ada16c2837d6af80ea6b237ba65975c01410418a808ea3fc6fd99c11b51f572d2e85b25a33048de2c0afda336c32da4619897629943638def6df1ab0d3acd35faa7e8c73ff1fc275677f82191b253a7bbf383
And the public key will be the following part:
48304502200a30a8634f41dbd92c007f937f6b0f220cc1f5a321252cc459092e45b1c5377802210
0caace1a19e1d195e8510ac290c13863f4ada16c2837d6af80ea6b237ba65975c0141
0418a808ea3fc6fd99c11b51f572d2e85b25a33048de2c0afda336c32da4619897629943638def6 df1ab0d3acd35faa7e8c73ff1fc275677f82191b253a7bbf383Here is the example of the full structure:
https://pastebin.com/Q55PyUgB