ddl: check no partitions error when create partition table

[crazycs520]

What problem does this PR solve?

In MySQL

mysql > create table t (a int not null) partition by range( a );
(1492, u'For RANGE partitions each partition must be defined')
mysql > create table t (a int not null) partition by range columns ( a );
(1492, u'For RANGE partitions each partition must be defined')
mysql > create table th (a int, b int) partition by hash(a) partitions 0;
(1504, u'Number of partitions = 0 is not an allowed value')

But in TiDB will execute those sql successful. then add index in this no partition table will panic.

Other check, drop partition will have check if drop the last partition and return ErrDropLastPartition, so drop partition will not cause the no partition table problem.

What is changed and how it works?

Add check when create partition table.

Check List

Tests

• Unit test

Code changes

• Has exported function/method change

Side effects

Related changes

• Need to cherry-pick to the release branch

[crazycs520]

/run-all-tests

[crazycs520]

@tiancaiamao @winkyao @zimulala PTAL

[codecov-io]

Codecov Report

Merging #9531 into master will increase coverage by 0.015%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##           master      #9531       +/-   ##
=============================================
+ Coverage   67.38%   67.3951%   +0.015%     
=============================================
  Files         374        374               
  Lines       78921      78936       +15     
=============================================
+ Hits        53177      53199       +22     
+ Misses      20991      20987        -4     
+ Partials     4753       4750        -3

[zhouqiang-cl]

/run-all-tests

[tiancaiamao]

LGTM

[zimulala]

LGTM

[winkyao]

LGTM