Extend references with new SHowSchemas type

Make resolve_table_ref as pub

Fix docs linter

Add DDL AlterTable

Add DDL AlterTable

Add "rlike" as an alias for regexp_like (#2)

* Add "rlike" as an alias for regexp_like

* Update docs

Extend references with new ShowSchemas type (#4)

* Extend references with new SHowSchemas type

* Make resolve_table_ref as pub

* Fix docs linter

Fix deps

Import alter table

Temp

Temp

Add regexp_substr udf

Add regexp_substr udf

Add regexp_substr udf

Add regexp_substr udf

Author: osipovartem

datafusion/core/src/catalog_common/mod.rs

@@ -156,6 +156,8 @@ pub fn resolve_table_references(
                     | Statement::ShowColumns { .. }
                     | Statement::ShowTables { .. }
                     | Statement::ShowCollation { .. }
+                    | Statement::ShowSchemas { .. }
+                    | Statement::ShowDatabases { .. }
             );
             if requires_information_schema {
                 for s in INFORMATION_SCHEMA_TABLES {

datafusion/core/src/execution/session_state.rs

@@ -285,7 +285,9 @@ impl SessionState {
             .build()
     }
 
-    pub(crate) fn resolve_table_ref(
+    /// Resolves a [`TableReference`] to a [`ResolvedTableReference`]
+    /// using the default catalog and schema.
+    pub fn resolve_table_ref(
         &self,
         table_ref: impl Into<TableReference>,
     ) -> ResolvedTableReference {
@@ -845,9 +847,9 @@ impl SessionState {
         overwrite: bool,
     ) -> Result<(), DataFusionError> {
         let ext = file_format.get_ext().to_lowercase();
-        match (self.file_formats.entry(ext.clone()), overwrite){
-            (Entry::Vacant(e), _) => {e.insert(file_format);},
-            (Entry::Occupied(mut e), true)  => {e.insert(file_format);},
+        match (self.file_formats.entry(ext.clone()), overwrite) {
+            (Entry::Vacant(e), _) => { e.insert(file_format); }
+            (Entry::Occupied(mut e), true) => { e.insert(file_format); }
             (Entry::Occupied(_), false) => return config_err!("File type already registered for extension {ext}. Set overwrite to true to replace this extension."),
         };
         Ok(())

datafusion/functions/src/regex/mod.rs

@@ -23,12 +23,14 @@ pub mod regexpcount;
 pub mod regexplike;
 pub mod regexpmatch;
 pub mod regexpreplace;
+pub mod regexpsubstr;
 
 // create UDFs
 make_udf_function!(regexpcount::RegexpCountFunc, regexp_count);
 make_udf_function!(regexpmatch::RegexpMatchFunc, regexp_match);
 make_udf_function!(regexplike::RegexpLikeFunc, regexp_like);
 make_udf_function!(regexpreplace::RegexpReplaceFunc, regexp_replace);
+make_udf_function!(regexpsubstr::RegexpSubstrFunc, regexp_substr);
 
 pub mod expr_fn {
     use datafusion_expr::Expr;
@@ -60,6 +62,31 @@ pub mod expr_fn {
         super::regexp_match().call(args)
     }
 
+    /// Returns the substring that matches a regular expression within a string.
+    pub fn regexp_substr(
+        values: Expr,
+        regex: Expr,
+        start: Option<Expr>,
+        occurrence: Option<Expr>,
+        flags: Option<Expr>,
+        group_num: Option<Expr>,
+    ) -> Expr {
+        let mut args = vec![values, regex];
+        if let Some(start) = start {
+            args.push(start);
+        };
+        if let Some(occurrence) = occurrence {
+            args.push(occurrence);
+        };
+        if let Some(flags) = flags {
+            args.push(flags);
+        };
+        if let Some(group_num) = group_num {
+            args.push(group_num);
+        };
+        super::regexp_substr().call(args)
+    }
+
     /// Returns true if a has at least one match in a string, false otherwise.
     pub fn regexp_like(values: Expr, regex: Expr, flags: Option<Expr>) -> Expr {
         let mut args = vec![values, regex];

datafusion/functions/src/regex/regexplike.rs

@@ -35,6 +35,7 @@ use std::sync::{Arc, OnceLock};
 #[derive(Debug)]
 pub struct RegexpLikeFunc {
     signature: Signature,
+    aliases: Vec<String>,
 }
 
 impl Default for RegexpLikeFunc {
@@ -84,6 +85,7 @@ impl RegexpLikeFunc {
                 vec![TypeSignature::String(2), TypeSignature::String(3)],
                 Volatility::Immutable,
             ),
+            aliases: vec![String::from("rlike")],
         }
     }
 }
@@ -112,6 +114,10 @@ impl ScalarUDFImpl for RegexpLikeFunc {
         })
     }
 
+    fn aliases(&self) -> &[String] {
+        &self.aliases
+    }
+
     fn invoke_batch(
         &self,
         args: &[ColumnarValue],