`show create table` equivalent in oracle sql

If you are asking about SQL*Plus commands (show create table table_name doesn't appear to be a SQL statement), you can use the desc command

SQL> desc emp
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPNO                                     NOT NULL NUMBER(4)
 ENAME                                              VARCHAR2(10)
 JOB                                                VARCHAR2(9)
 MGR                                                NUMBER(4)
 HIREDATE                                           DATE
 SAL                                                NUMBER(7,2)
 COMM                                               NUMBER(7,2)
 DEPTNO                                             NUMBER(2)

If you really want a SQL statement, you can use the dbms_metadata package

  1  select dbms_metadata.get_ddl( 'TABLE', 'EMP', 'SCOTT' )
  2*   from dual
SQL> /

DBMS_METADATA.GET_DDL('TABLE','EMP','SCOTT')
--------------------------------------------------------------------------------

  CREATE TABLE "SCOTT"."EMP"
   (    "EMPNO" NUMBER(4,0),
        "ENAME" VARCHAR2(10),
        "JOB" VARCHAR2(9),
        "MGR" NUMBER(4,0),
        "HIREDATE" DATE,
        "SAL" NUMBER(7,2),
        "COMM" NUMBER(7,2),
        "DEPTNO" NUMBER(2,0),
         CONSTRAINT "PK_EMP" PRIMARY KEY ("EMPNO")
  USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DE
FAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "USERS"
  ALTER INDEX "SCOTT"."PK_EMP"  UNUSABLE ENABLE,
         CONSTRAINT "FK_DEPTNO" FOREIGN KEY ("DEPTNO")
          REFERENCES "SCOTT"."DEPT" ("DEPTNO") ENABLE
   ) SEGMENT CREATION IMMEDIATE
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DE
FAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "USERS"
  CACHE

Depending on the tool you are using, you may need to run set long 10000 first, that tells SQL*Plus to display the first 10,000 bytes of any LOB that is selected. If your DDL is longer, set a larger value.

SQL> set long 1000
SQL> set pagesize 0
SQL> select DBMS_METADATA.GET_DDL('TABLE','TABLE NAME'[,'SCHEMA']) from DUAL

Use DESC:

DESC mytable

Will show you the columns, but unfortunately the create statement is not available using standard oracle tools.