Oracle 18c

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CREATE TABLE test_data ( exponent NUMBER(3,0), value NUMBER );
INSERT INTO test_data ( exponent, value ) VALUES ( 125, 9.9999999999999999999999999999999999999e125);
1 rows affected

INSERT INTO test_data ( exponent, value ) VALUES ( 125, -9.9999999999999999999999999999999999999e125 );
1 rows affected

INSERT INTO test_data ( exponent, value ) VALUES ( 126, 9.9999999999999999999999999999999999999e126 );
ORA-01426: numeric overflow

INSERT INTO test_data ( exponent, value ) VALUES ( 126, -9.9999999999999999999999999999999999999e126 );
ORA-01426: numeric overflow

INSERT INTO test_data ( exponent, value ) VALUES ( -130, -9.9999999999999999999999999999999999999e-130 );
1 rows affected

INSERT INTO test_data ( exponent, value ) VALUES ( -131, -9.9999999999999999999999999999999999999e-131 );
1 rows affected

SELECT exponent,
       LENGTH( cast(value as varchar2(200 char)) ) AS len,
       CAST(value AS VARCHAR2(200 CHAR)) AS string
FROM   test_data;


EXPONENT
LEN
STRING


125
126
999999999999999999999999999999999999990000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

125
127
-999999999999999999999999999999999999990000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

-130
169
-.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000099999999999999999999999999999999999999

-131
1
0

EXPONENT	LEN	STRING
125	126	999999999999999999999999999999999999990000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
125	127	-999999999999999999999999999999999999990000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-130	169	-.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000099999999999999999999999999999999999999
-131	1	0