qstommyshu commented on code in PR #15736:
URL: https://github.com/apache/datafusion/pull/15736#discussion_r2047992548
##########
datafusion/sql/src/parser.rs:
##########
@@ -469,9 +473,101 @@ impl<'a> DFParser<'a> {
}
_ => {
// use sqlparser-rs parser
- Ok(Statement::Statement(Box::from(
- self.parser.parse_statement()?,
- )))
+ let mut stmt = self.parser.parse_statement()?;
+
+ use sqlparser::ast::{DataType, Expr, Spanned, Value};
+
+ if let sqlparser::ast::Statement::Query(query) = &mut
stmt {
+ if let sqlparser::ast::SetExpr::Select(select) =
+ &mut *query.body
+ {
+ // if missing from
+ if select.from.is_empty() {
+ let mut new_projection = Vec::new();
+
+ for expr in &select.projection {
+ match expr {
+
sqlparser::ast::SelectItem::UnnamedExpr(
+ cast_expr,
+ ) => {
+ if let Expr::Cast {
+ expr: inner_expr,
+ data_type,
+ ..
+ } = cast_expr
+ {
+ let inner_str = match
&**inner_expr {
+
Expr::Value(sqlparser::ast::ValueWithSpan { value:
Value::SingleQuotedString(s), .. }) => {
+
format!("'{}'", s)
+ },
+
Expr::Value(sqlparser::ast::ValueWithSpan { value: Value::Number(n, _), .. })
=> {
+ n.clone()
+ },
+ // TODO: need to
take care of other types of values, like TimeStamp, etc...
+ _ =>
format!("{:?}", inner_expr),
+ };
+
+ // get cast to type string
+ let type_str = match
data_type {
+ DataType::Int(_) =>
"INT",
+ DataType::BigInt(_) =>
"BIGINT",
+ DataType::SmallInt(_)
=> {
+ "SMALLINT"
+ }
+ DataType::Boolean =>
"BOOLEAN",
+ DataType::Varchar(_)
=> "VARCHAR",
+ DataType::Float(_) =>
"FLOAT",
+ DataType::Double(_) =>
"DOUBLE",
+ DataType::Text =>
"TEXT",
+ // TODO: need to
support more DataType, probably use an Extension Trait
Review Comment:
Currently, supported data type result would look like this:
`select cast('1' as int);`
```
+------------------+
| cast('1' as int) |
+------------------+
| 1 |
+------------------+
```
unsupported data type result would look like this:
`select cast(1 as string);`
```
+-------------------------+
| cast(1 as string(none)) |
+-------------------------+
| 1 |
+-------------------------+
```
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