如果您问sql * Plus命令(show create table table_name似乎不是sql语句)，可以使用desc命令

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)

如果你真的想要一个sql语句，你可以使用dbms_Metadata包

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

DBMS_MetaDATA.GET_DDL('TABLE','SCOTT')
--------------------------------------------------------------------------------

  CREATE TABLE "SCOTT"."EMP"
   (    "EMPNO" NUMBER(4,0),"ENAME" VARCHAR2(10),"JOB" VARCHAR2(9),"MGR" NUMBER(4,"HIREDATE" DATE,"SAL" NUMBER(7,2),"COMM" NUMBER(7,"DEPTNO" NUMBER(2,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

根据您使用的工具，您可能需要首先运行set long 10000，这将告诉sql * Plus显示所选LOB的前10,000个字节。如果您的DDL较长，请设置较大的值。