diff --git a/.github/workflows/crystal.yml b/.github/workflows/crystal.yml
new file mode 100644
index 0000000..ade0241
--- /dev/null
+++ b/.github/workflows/crystal.yml
@@ -0,0 +1,22 @@
+name: Crystal CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    container:
+      image: crystallang/crystal
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install dependencies
+      run: shards install
+    - name: Run tests
+      run: crystal spec
diff --git a/README.md b/README.md
index 76af28a..a07b91c 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,134 @@
 # Procedural-Language-for-SQL-Query
 # Procedural-Language-for-SQL-Query
+PL/SQL offers the concatenation operator (||) for joining two strings. The following table provides the string functions provided by PL/SQL −
+
+S.No	Function & Purpose
+1	
+ASCII(x);
+
+Returns the ASCII value of the character x.
+
+2	
+CHR(x);
+
+Returns the character with the ASCII value of x.
+
+3	
+CONCAT(x, y);
+
+Concatenates the strings x and y and returns the appended string.
+
+4	
+INITCAP(x);
+
+Converts the initial letter of each word in x to uppercase and returns that string.
+
+5	
+INSTR(x, find_string [, start] [, occurrence]);
+
+Searches for find_string in x and returns the position at which it occurs.
+
+6	
+INSTRB(x);
+
+Returns the location of a string within another string, but returns the value in bytes.
+
+7	
+LENGTH(x);
+
+Returns the number of characters in x.
+
+8	
+LENGTHB(x);
+
+Returns the length of a character string in bytes for single byte character set.
+
+9	
+LOWER(x);
+
+Converts the letters in x to lowercase and returns that string.
+
+10	
+LPAD(x, width [, pad_string]) ;
+
+Pads x with spaces to the left, to bring the total length of the string up to width characters.
+
+11	
+LTRIM(x [, trim_string]);
+
+Trims characters from the left of x.
+
+12	
+NANVL(x, value);
+
+Returns value if x matches the NaN special value (not a number), otherwise x is returned.
+
+13	
+NLS_INITCAP(x);
+
+Same as the INITCAP function except that it can use a different sort method as specified by NLSSORT.
+
+14	
+NLS_LOWER(x) ;
+
+Same as the LOWER function except that it can use a different sort method as specified by NLSSORT.
+
+15	
+NLS_UPPER(x);
+
+Same as the UPPER function except that it can use a different sort method as specified by NLSSORT.
+
+16	
+NLSSORT(x);
+
+Changes the method of sorting the characters. Must be specified before any NLS function; otherwise, the default sort will be used.
+
+17	
+NVL(x, value);
+
+Returns value if x is null; otherwise, x is returned.
+
+18	
+NVL2(x, value1, value2);
+
+Returns value1 if x is not null; if x is null, value2 is returned.
+
+19	
+REPLACE(x, search_string, replace_string);
+
+Searches x for search_string and replaces it with replace_string.
+
+20	
+RPAD(x, width [, pad_string]);
+
+Pads x to the right.
+
+21	
+RTRIM(x [, trim_string]);
+
+Trims x from the right.
+
+22	
+SOUNDEX(x) ;
+
+Returns a string containing the phonetic representation of x.
+
+23	
+SUBSTR(x, start [, length]);
+
+Returns a substring of x that begins at the position specified by start. An optional length for the substring may be supplied.
+
+24	
+SUBSTRB(x);
+
+Same as SUBSTR except that the parameters are expressed in bytes instead of characters for the single-byte character systems.
+
+25	
+TRIM([trim_char FROM) x);
+
+Trims characters from the left and right of x.
+
+26	
+UPPER(x);
+
+Converts the letters in x to uppercase and returns that string.