FIRST
and SKIP
with NULL
argument
FIRST
and SKIP
crash a Firebird 1.5.n or lower server if given a NULL
argument.Fixed in 2.0.
Internal functions and directives
Conditional statements and loops
Changing the nullability of a domain
Testing for NULL and equality in practice
Firebird Null Guide: NULL behaviour and pitfalls in Firebird SQL
FIRST
and SKIP
with NULL
argumentFIRST
and SKIP
crash a Firebird 1.5.n or lower server if given a NULL
argument.Fixed in 2.0.
LIKE
with NULL
escapeUsing LIKE
with a NULL
escape character would crash the server.Fixed in 1.5.1.
NULL
s in NOT NULL
columnsNULL
s can exist in NOT NULL
columns in the following situations:
If you add a NOT NULL
column to a populated table, the fields in the newly added column will all be NULL
.
If you make an existing column NOT NULL
, any NULL
s already present in the column will remain in that state.
Firebird allows these NULL
s to stay, also backs them up, but refuses to restore them with gbak
.See [nullguide-add-not-null-field] and [nullguide-make-column-not-null].