## Proposed changes
Infer the column name when create view if the column is expression
## Further comments
expr column name infer strategy as following:
| expr | example | column name(before) | Inferred column name(if position is 2) |
| ------------- | --------------------------------------- | ------------------------------ | -------------------------------------- |
| function | dayofyear() | dayofyear() | __dayofyear_1 |
| cast | cast(1 as bigint) | CAST(1 AS BIGINT) | __cast_1 |
| anylyticExpr | min() | min() | __min_1 |
| predicate | 1 in (1,2,3,4) | 1 IN (1, 2, 3, 4) | __in_predicate_1 |
| literal | 1 or 'string_var_name' | 1 or 'string_var_name' | __literal_1 |
| arithmeticExpr | & | ... & ... | __arithmetic_expr_1 |
| identifier | a or b | a or b | a or b |
| case | CASE WHEN remark = 's' THEN 1 ELSE 2 END | CASE WHEN remark = 's' THEN 1 ELSE 2 END | __case_1 |
| window | min(timestamp) OVER (...) | min(timestamp) OVER(...) | __min_1 |
SQL for example:
```sql
CREATE VIEW v1 AS
SELECT
error_code,
1,
'string',
now(),
dayofyear(op_time),
cast (source AS BIGINT),
min(`timestamp`) OVER (
ORDER BY
op_time DESC ROWS BETWEEN UNBOUNDED PRECEDING
AND 1 FOLLOWING
),
1 > 2,
2 + 3,
1 IN (1, 2, 3, 4),
remark LIKE '%like',
CASE WHEN remark = 's' THEN 1 ELSE 2 END,
TRUE | FALSE
FROM
db_test.table_test1
```
the output column name is as following:
```
error_code
__literal_1
__literal_2
__now_3
__dayofyear_4
__cast_expr_5
__min_6
__binary_predicate_7
__arithmetic_expr_8
__in_predicate_9
__like_predicate_10
__case_expr_11
__arithmetic_expr_12
```
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