use ilike for case insensitive search in PostgreSql

Author: ahmad-moussawi

QueryBuilder.Tests/SelectTests.cs

@@ -700,6 +700,17 @@ public void MultipleOrHaving()
             Assert.Equal("SELECT * FROM [Table1] HAVING [Column1] > 1 OR [Column2] = 1", c[EngineCodes.SqlServer]);
         }
 
+        [Fact]
+        public void ShouldUseILikeOnPostgresWhenNonCaseSensitive()
+        {
+            var q = new Query("Table1")
+                .WhereLike("Column1", "%Upper Word%", false);
+            var c = Compile(q);
+
+            Assert.Equal(@"SELECT * FROM [Table1] WHERE LOWER([Column1]) like '%upper word%'", c[EngineCodes.SqlServer]);
+            Assert.Equal("SELECT * FROM \"Table1\" WHERE \"Column1\" ilike '%Upper Word%'", c[EngineCodes.PostgreSql]);
+        }
+
         [Fact]
         public void EscapedWhereLike()
         {

QueryBuilder/Compilers/PostgresCompiler.cs

@@ -1,3 +1,6 @@
+using System;
+using System.Linq;
+
 namespace SqlKata.Compilers
 {
     public class PostgresCompiler : Compiler
@@ -9,6 +12,60 @@ public PostgresCompiler()
 
         public override string EngineCode { get; } = EngineCodes.PostgreSql;
 
+
+        protected override string CompileBasicStringCondition(SqlResult ctx, BasicStringCondition x)
+        {
+
+            var column = Wrap(x.Column);
+
+            var value = Resolve(ctx, x.Value) as string;
+
+            if (value == null)
+            {
+                throw new ArgumentException("Expecting a non nullable string");
+            }
+
+            var method = x.Operator;
+
+            if (new[] { "starts", "ends", "contains", "like", "ilike" }.Contains(x.Operator))
+            {
+                method = x.CaseSensitive ? "LIKE" : "ILIKE";
+
+                switch (x.Operator)
+                {
+                    case "starts":
+                        value = $"{value}%";
+                        break;
+                    case "ends":
+                        value = $"%{value}";
+                        break;
+                    case "contains":
+                        value = $"%{value}%";
+                        break;
+                }
+            }
+
+            string sql;
+
+            if (x.Value is UnsafeLiteral)
+            {
+                sql = $"{column} {checkOperator(method)} {value}";
+            }
+            else
+            {
+                sql = $"{column} {checkOperator(method)} {Parameter(ctx, value)}";
+            }
+
+            if (!string.IsNullOrEmpty(x.EscapeCharacter))
+            {
+                sql = $"{sql} ESCAPE '{x.EscapeCharacter}'";
+            }
+
+            return x.IsNot ? $"NOT ({sql})" : sql;
+
+        }
+
+
         protected override string CompileBasicDateCondition(SqlResult ctx, BasicDateCondition condition)
         {
             var column = Wrap(condition.Column);