[fix](doc)Fix sql function doc

[BenjaminWenqiYu]

Proposed changes

should use CURRENT_DATE to obtain the correct result Issue Number: close #12544

Problem summary

should use CURRENT_DATE to obtain the correct result.

Checklist(Required)

1. Does it affect the original behavior:
   • [ ] Yes
   • [x] No
   • [ ] I don't know
2. Has unit tests been added:
   • [ ] Yes
   • [x] No
   • [ ] No Need
3. Has document been added or modified:
   • [x] Yes
   • [ ] No
   • [ ] No Need
4. Does it need to update dependencies:
   • [ ] Yes
   • [x] No
5. Are there any changes that cannot be rolled back:
   • [ ] Yes (If Yes, please explain WHY)
   • [x] No

Further comments

If this is a relatively large or complex change, kick off the discussion at [email protected] by explaining why you chose the solution you did and what alternatives you considered, etc...

[BenjaminWenqiYu]

@Gabriel39 Hi, when I use CURDATE, it got another result but not what I expected.

[Gabriel39]

@Gabriel39 Hi, when I use CURDATE, it got another result but not what I expected.

@BenjaminWenqiYu Actually this is a bug not a document mistake. And I fixed this bug by #12720 . You can double check this problem and I will close this PR if you have no other problems. Thanks!