add syntax, examples

Author: llouislu

README.md

@@ -4,7 +4,7 @@ Compare Difference In T-SQL Queries at Runtime
 ![CI Status](https://travis-ci.org/llouislu/tsql-diff.svg?branch=master) ![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)
 
 ## Install
-1. Go to [release](https://github.com/llouislu/tsql-diff/releases) and download the latest version.
+1. Go to [release](https://github.com/llouislu/tsql-diff/releases) and download the latest **Release** version.
 2. execute install.sql in your target database.
 
 ## Uninstall
@@ -19,19 +19,87 @@ Please refer to the doc/examples while reading this section.
 There is a `Diff` schema in your target database after you successfully installed this library.
 
 ### Compare two queries in strings
+#### Syntax
+```sql
+Diff.CompareString
+    @EXP_QueryString NVARCHAR(max),
+    -- expected query string 
+    @ACT_QueryString NVARCHAR(max),
+    -- actual query string
+    @ExplicitColumnOrder TINYINT = 1,
+    -- optional, set default value 1 to compare column order
+    @ExplicitColumnName TINYINT = 1,
+    -- optional, set default value 1 to compare column name(s)
+    @CompareData TINYINT = 1
+    -- optionalset default valueet 1 to reorder data rows and compare the difference
+```
+#### Output
+- An `INT`, a sum of error values
+- Detailed difference in log
+#### Example
 ```sql
 DECLARE @status_code INT;
 EXEC @status_code = Diff.CompareString 'Select 1', 'Select 2';
 ```
 
 ### Compare two queries in files
+#### Syntax
+```sql
+Diff.Compare
+    @ExpectedFilePath NVARCHAR(max),
+    -- file path of expected query
+    @ActualFilePath NVARCHAR(max),
+    -- file path of actual query
+    @ExplicitColumnOrder TINYINT = 1,
+    -- optional, set default value 1 to compare column order
+    @ExplicitColumnName TINYINT = 1,
+    -- optional, set default value 1 to compare column name(s)
+    @CompareData TINYINT = 1
+    -- optionalset default valueet 1 to reorder data rows and compare the difference
+```
+#### Output
+- An `INT`, a sum of error values
+- Detailed difference in log
+#### Example
 ```sql
 DECLARE @status_code INT;
 EXEC @status_code = Diff.Compare 'path/to/query1.sql', 'path/to/query2.sql';
 ```
 
 ### Compare pairs of queries in a folder
+#### Syntax
+```sql
+Diff.CompareFolder
+    @FolderPath NVARCHAR(1024) = N'/root/data/t',
+    -- location of a folder where T-SQL files are stored
+    -- accepts both blackslashes on Windows and forwardslashes on *nix
+    @ModifierName NVARCHAR(32) = N'Model',
+    -- a filename suffix in  identifying the current file as an anchor/master/standard/expected query
+    -- e.g. In the filename 'q01Model.sql', 'Model' indicates the file is marked as correct.
+    @FileSuffix NVARCHAR(8) = N'.sql'
+    -- a filename extension of T-SQL files
+```
+#### Output
+- Detailed difference in log
+#### Example
 ```sql
 declare @status_code INT;
-exec Diff.ComapreFolder @FolderPath='/root/data/t', @ModifierName='Model'
+exec Diff.ComapreFolder @FolderPath='/test', @ModifierName='Model'
 ```
+
+### Error Values
+| value | error                                      |
+|:-----:|--------------------------------------------|
+| 1     | runtime error or no valid select statement |
+| 2     | expected column datatype(s) not matched    |
+| 4     | column order not matched                   |
+| 8     | column names not matched                   |
+| 16    | data row not matched                       |
+
+### Limitations
+
+- T-SQL Diff only receives the first `SELECT` statement as input to compare.
+
+- `WITH` statements (e.g. cte) in `SELECT` are not supported
+
+- Custom datatypes defined by CLR are not supported