mysql - SQL Syntax using CONCAT -



mysql - SQL Syntax using CONCAT -

i have table t1 fields

id,key_id ,name,date etc.. id auto incrementing field key_id value obtained id prefix/id prefix constant rows , id changes id corresponding row..

it looks this

$sql = " alter table t1 auto_increment = 1234567890, add together id bigint not null primary key auto_increment "; update t1 set key_id = concat('12.345','/',id)

now due reasons want create new table t2 parent of t1 , id primary key t2 , key_id become primary key of t1. t2 should include other 2 fields key_id , name..

ok main reason parent table : might create table t3 have id , id should have different values t1 , t3 want maintain master table has id primary key , other kid tables fetch ids master table..

how can this?

why want store redundant info in column "key_id"?

since prefix constant, id enough. perform concatenation in code.

also, way, can have id primary key both tables , key_id prefixing "prefix".

mysql sql sql-update

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