Question

I’m Noob in SQL.

Ive 3 tables:

TB_ITEM
{
    TB_ITEM_ID int primary key,
    TB_ITEM_CAT_ID int,
    TB_ITEM_SUBCAT_ID int,
    TB_ITEM_NAME varchar(350)
    add constraint FK_ITEM_CAT foreign key(TB_ITEM_CAT_ID)
    references TB_ITEM_CAT(TB_ITEM_CAT_ID),
    add constraint FK_ITEM_SUBCAT foreign key(TB_ITEM_SUBCAT_ID)
    references TB_ITEM_SUBCAT(TB_ITEM_SUBCAT_ID)
}
TB_ITEM_CAT
{
    TB_ITEM_CAT_ID int primary key,
    TB_ITEM_CAT_NAME varchar(350)
}
TB_ITEM_SUBCAT
{
    TB_ITEM_SUBCAT_ID int primary key,
    TB_ITEM_CAT_ID int,
    TB_ITEM_SUBCAT_NAME
    add constraint FK_CAT foreign key(TB_ITEM_CAT_ID)
    references TB_ITEM_CAT(TB_ITEM_CAT_ID)
}

TABLE “TB_ITEM” HAS 416 RECORDS.

Ive tried,follow query:

select a.TB_ITEM_NAME, b.TB_ITEM_CAT_NAME, c.TB_ITEM_SUBCAT_NAME from 
TB_ITEM a inner join 
TB_ITEM_CAT b on a.TB_ITEM_CAT_ID = b.TB_ITEM_CAT_ID 
   inner join TB_ITEM_SUBCAT c 
on a.TB_ITEM_SUBCAT_ID = c.TB_ITEM_SUBCAT_ID

and result is:1162 results

I mean:I want to retrieve only those 416 records from TB_ITEM and its CATEGORIES NAMES and SUB-CATEGORIES NAME
from TB_ITEM_CAT and TB_ITEM_SUBCAT

Is this query wrong?Why 1162 records instead only 416?

Any ideias?

Answer 1

You will need to ensure that TB_ITEM_SUBCAT is joined correctly to avoid duplicates

See if this works:

 select a.TB_ITEM_NAME, b.TB_ITEM_CAT_NAME, c.TB_ITEM_SUBCAT_NAME from 
 TB_ITEM a inner join 
 TB_ITEM_CAT b on a.TB_ITEM_CAT_ID = b.TB_ITEM_CAT_ID 
 inner join TB_ITEM_SUBCAT c 
 on a.TB_ITEM_SUBCAT_ID = c.TB_ITEM_SUBCAT_ID and a.TB_ITEM_CAT_ID = c.TB_ITEM_CAT_ID