fix: optimizing 'alter table drop tag' error reporting

source/libs/parser/src/parTranslater.c

@@ -5155,28 +5155,32 @@ static int32_t checkAlterSuperTableBySchema(STranslateContext* pCxt, SAlterTable
     return generateSyntaxErrMsg(&pCxt->msgBuf, TSDB_CODE_PAR_ONLY_ONE_JSON_TAG);
   }
 
-  if (getNumOfTags(pTableMeta) == 1 && pStmt->alterType == TSDB_ALTER_TABLE_DROP_TAG) {
-    return generateSyntaxErrMsgExt(&pCxt->msgBuf, TSDB_CODE_PAR_INVALID_ALTER_TABLE, "the only tag cannot be dropped");
-  }
-
   int32_t tagsLen = 0;
   for (int32_t i = 0; i < pTableMeta->tableInfo.numOfTags; ++i) {
     tagsLen += pTagsSchema[i].bytes;
   }
 
   if (TSDB_ALTER_TABLE_UPDATE_COLUMN_BYTES == pStmt->alterType ||
-      TSDB_ALTER_TABLE_UPDATE_TAG_BYTES == pStmt->alterType) {
+      TSDB_ALTER_TABLE_UPDATE_TAG_BYTES == pStmt->alterType || TSDB_ALTER_TABLE_DROP_COLUMN == pStmt->alterType ||
+      TSDB_ALTER_TABLE_DROP_TAG == pStmt->alterType) {
     if (TSDB_SUPER_TABLE != pTableMeta->tableType) {
       return generateSyntaxErrMsgExt(&pCxt->msgBuf, TSDB_CODE_PAR_INVALID_ALTER_TABLE, "Table is not super table");
     }
 
     const SSchema* pSchema = getColSchema(pTableMeta, pStmt->colName);
     if (NULL == pSchema) {
-      return generateSyntaxErrMsg(&pCxt->msgBuf, TSDB_CODE_PAR_INVALID_COLUMN, pStmt->colName);
+      return generateSyntaxErrMsg(
+          &pCxt->msgBuf,
+          (TSDB_ALTER_TABLE_UPDATE_COLUMN_BYTES == pStmt->alterType || TSDB_ALTER_TABLE_DROP_COLUMN == pStmt->alterType)
+              ? TSDB_CODE_PAR_INVALID_COLUMN
+              : TSDB_CODE_PAR_INVALID_TAG_NAME,
+          pStmt->colName);
     }
 
-    if (!IS_VAR_DATA_TYPE(pSchema->type) || pSchema->type != pStmt->dataType.type ||
-        pSchema->bytes >= calcTypeBytes(pStmt->dataType)) {
+    if ((TSDB_ALTER_TABLE_UPDATE_COLUMN_BYTES == pStmt->alterType ||
+         TSDB_ALTER_TABLE_DROP_COLUMN == pStmt->alterType) &&
+        (!IS_VAR_DATA_TYPE(pSchema->type) || pSchema->type != pStmt->dataType.type ||
+         pSchema->bytes >= calcTypeBytes(pStmt->dataType))) {
       return generateSyntaxErrMsg(&pCxt->msgBuf, TSDB_CODE_PAR_INVALID_MODIFY_COL);
     }
 
@@ -5221,6 +5225,10 @@ static int32_t checkAlterSuperTableBySchema(STranslateContext* pCxt, SAlterTable
     }
   }
 
+  if (getNumOfTags(pTableMeta) == 1 && pStmt->alterType == TSDB_ALTER_TABLE_DROP_TAG) {
+    return generateSyntaxErrMsgExt(&pCxt->msgBuf, TSDB_CODE_PAR_INVALID_ALTER_TABLE, "the only tag cannot be dropped");
+  }
+
   return TSDB_CODE_SUCCESS;
 }