CASE 1: I have a table with 30 columns and I query using 4 columns in the where clause.
CASE 2: I have a table with 6 columns and I query using 4 columns in the whe
Depends on width of the table (Bytes per row), how many rows in the table, and whether there are indices on the columns used by the query. No definitive answer without that info. However, the more columns in the table, chances are it is wider. But the effect of a proper index is much more significant than the effect of the table size.