如何判断一个字符串是否含有汉字？

利用LENGTH、LENGTHB和TO_SINGLE_BYTE函数来解决这个问题。

SYS@lhrdb> CREATE TABLE AA (COL   VARCHAR2(255));

Table created.

SYS@lhrdb> INSERT INTO AA (COL) VALUES ('1');

1 row created.

SYS@lhrdb> INSERT INTO AA (COL) VALUES ('２');

1 row created.

SYS@lhrdb> INSERT INTO AA (COL) VALUES ('小麦苗');

1 row created.

SYS@lhrdb> COMMIT;

Commit complete.

SYS@lhrdb> SELECT * FROM AA;   

COL

----------

1

２

小麦苗

SYS@lhrdb> COL COL FORMAT A10

SYS@lhrdb> COL SINGLE_COL  FORMAT A10

SYS@lhrdb> SELECT A.COL COL,

  2         TO_SINGLE_BYTE(A.COL) SINGLE_COL,

  3         LENGTH(A.COL) LENGTH_COL,

  4         LENGTHB(A.COL) LENGTHB_COL,

  5         LENGTH(TO_SINGLE_BYTE(A.COL)) SINGLE_LENGTH_COL,

  6         LENGTHB(TO_SINGLE_BYTE(A.COL))  SINGLE_LENGTHB_COL

  7    FROM AA A

  8   WHERE LENGTHB(A.COL) <> LENGTH(A.COL)

  9     AND LENGTHB(TO_SINGLE_BYTE(A.COL)) <> LENGTH(TO_SINGLE_BYTE(A.COL));

COL        SINGLE_COL LENGTH_COL LENGTHB_COL SINGLE_LENGTH_COL SINGLE_LENGTHB_COL

---------- ---------- ---------- ----------- ----------------- ------------------

小麦苗     小麦苗              3           6                 3                  6