Merge pull request #469 from slabko/fix-locate-start-pos

Fix issues with the locate function call

Author: slabko

driver/escaping/escape_sequences.cpp

@@ -234,9 +234,19 @@ string processFunction(const StringView seq, Lexer & lex) {
         lex.Consume();
 
         auto offset = processIdentOrFunction(seq, lex /*, false */);
-        lex.Consume();
+        if (offset.empty()) {
+            offset = "1";
+        } else {
+            lex.Consume();
+        }
 
-        result = "position(" + haystack + "," + needle + ")";
+        // ClickHouse requires `start_pos` to be an unsigned integer,
+        // whereas ODBC clients map it as a signed integer. This results in
+        // a named parameter such as `{odbc_positional_:Int32}`, which does not
+        // match the type required by `locate`. To avoid the illegal type argument
+        // error, we cast the offset parameter to UInt64. The `accurateCast` function
+        // ensures that the parameter value is never negative.
+        result = "locate(" + needle + "," + haystack + ",accurateCast(" + offset + ",'UInt64'))";
 
         return result;
 

driver/test/escape_sequences_ut.cpp

@@ -298,8 +298,21 @@ TEST(EscapeSequencesCase, DateTime) {
 }
 
 TEST(EscapeSequencesCase, LOCATE) {
-    ASSERT_EQ(replaceEscapeSequences("{fn LOCATE('Xsell',`dm_ExperimentsData`.`ProductLevel`,1)}"),
-        "position(`dm_ExperimentsData`.`ProductLevel`,'Xsell')");
+    ASSERT_EQ(replaceEscapeSequences(
+        "SELECT {fn LOCATE('needle', `haystack`, 42)}"),
+        "SELECT locate('needle',`haystack`,accurateCast(42,'UInt64'))");
+    ASSERT_EQ(replaceEscapeSequences(
+        "SELECT {fn LOCATE(?, `haystack`, 42)}"),
+        "SELECT locate(?,`haystack`,accurateCast(42,'UInt64'))");
+    ASSERT_EQ(replaceEscapeSequences(
+        "SELECT {fn LOCATE('needle', `haystack`, ?)}"),
+        "SELECT locate('needle',`haystack`,accurateCast(?,'UInt64'))");
+    ASSERT_EQ(replaceEscapeSequences(
+        "SELECT {fn LOCATE('needle', `haystack`)}"),
+        "SELECT locate('needle',`haystack`,accurateCast(1,'UInt64'))");
+    ASSERT_EQ(replaceEscapeSequences(
+        "SELECT {fn LOCATE(?, `haystack`)}"),
+        "SELECT locate(?,`haystack`,accurateCast(1,'UInt64'))");
 }
 
 TEST(EscapeSequencesCase, LCASE) {