fixes #3252

fixes #3252

also improved unit tests for querybuilder buildLikeCondition

Fixes #3268: Fixed the bug that the schema name in a table name was not respected by `yii\db\mysql\Schema`

[ci skip]

```
PHP Notice – yii\base\ErrorException

Undefined offset: 3

in .../yiisoft/yii2/db/QueryTrait.php at line 269
```

Adjustments code according to the standards.
Adding missing PHPDoc comment.

Fixes #3066: `yii\db\mssql\Schema::getTableSchema()` should return null when the table does not exist.

PHPDoc comment does not match function or method signature
Update PHPDoc Comment

Adjust code standard

issue #3026

fixes #3034

New addSelect method. Useful for scopes.