feat(engine/dolphin): implement MATCH_AGAINST conversion in SQL AST (sqlc-dev#1192, sqlc-dev#3091) (sqlc-dev#4070)

* add conversion logic for MATCH_AGAINST statements * create type casting for search terms to 'text' * construct A_Expr for MATCH_AGAINST operation Co-authored-by: Vladimir Kochergin <vladimir.kochergin@check24.de>

Author: wawan93

internal/engine/dolphin/convert.go

@@ -989,7 +989,30 @@ func (c *cc) convertLockTablesStmt(n *pcast.LockTablesStmt) ast.Node {
 }
 
 func (c *cc) convertMatchAgainst(n *pcast.MatchAgainst) ast.Node {
-return todo(n)
+searchTerm := c.convert(n.Against)
+
+stringSearchTerm := &ast.TypeCast{
+Arg: searchTerm,
+TypeName: &ast.TypeName{
+Name: "text", // Use 'text' type which maps to string in Go
+},
+Location: n.OriginTextPosition(),
+}
+
+matchOperation := &ast.A_Const{
+Val: &ast.String{Str: "MATCH_AGAINST"},
+}
+
+return &ast.A_Expr{
+Name: &ast.List{
+Items: []ast.Node{
+&ast.String{Str: "AGAINST"},
+},
+},
+Lexpr: matchOperation,
+Rexpr: stringSearchTerm,
+Location: n.OriginTextPosition(),
+}
 }
 
 func (c *cc) convertMaxValueExpr(n *pcast.MaxValueExpr) ast.Node {