Add sql char length functions

dialects/hsql/src/main/kotlin/app/cash/sqldelight/dialects/hsql/HsqlTypeResolver.kt

@@ -45,6 +45,7 @@ class HsqlTypeResolver(private val parentResolver: TypeResolver) : TypeResolver
     "coalesce", "ifnull" -> encapsulatingType(exprList, TINY_INT, SMALL_INT, HsqlType.INTEGER, INTEGER, BIG_INT, REAL, TEXT, BLOB)
     "max" -> encapsulatingType(exprList, TINY_INT, SMALL_INT, HsqlType.INTEGER, INTEGER, BIG_INT, REAL, TEXT, BLOB).asNullable()
     "min" -> encapsulatingType(exprList, BLOB, TEXT, TINY_INT, SMALL_INT, INTEGER, HsqlType.INTEGER, BIG_INT, REAL).asNullable()
+    "length", "char_length", "character_length" -> IntermediateType(BIG_INT).nullableIf(resolvedType(exprList[0]).javaType.isNullable)
     else -> null
   }
 }

dialects/mysql/src/main/kotlin/app/cash/sqldelight/dialects/mysql/MySqlTypeResolver.kt

@@ -69,6 +69,7 @@ class MySqlTypeResolver(
     "to_seconds" -> IntermediateType(INTEGER)
     "json_arrayagg" -> IntermediateType(TEXT)
     "date_add", "date_sub" -> IntermediateType(TEXT)
+    "char_length", "character_length" -> IntermediateType(INTEGER).nullableIf(resolvedType(exprList[0]).javaType.isNullable)
     else -> null
   }
 

dialects/mysql/src/test/fixtures_mysql/alter-table-add-constraint-check/1.s

@@ -1,6 +1,12 @@
 CREATE TABLE t1 (
-  c1 int(11)
+  c1 int(11),
+  t1 TEXT,
+  t2 VARCHAR(255),
+  t3 CHAR(10)
 );
 
 ALTER TABLE t1
- ADD CONSTRAINT chk_c1 CHECK (c1 > 0);
+  ADD CONSTRAINT chk_c1 CHECK (c1 > 0),
+  ADD CONSTRAINT chk_t1 CHECK (LENGTH(t1) > 0),
+  ADD CONSTRAINT chk_t2 CHECK (CHAR_LENGTH(t2) > 0),
+  ADD CONSTRAINT chk_t3 CHECK (CHARACTER_LENGTH(t3) > 0);

sqldelight-gradle-plugin/src/test/integration-hsql/src/main/sqldelight/app/cash/sqldelight/hsql/integration/Characters.sq

@@ -0,0 +1,13 @@
+CREATE TABLE characters (
+  name VARCHAR(255) NOT NULL,
+  description VARCHAR(255)
+);
+
+insertCharacter:
+  INSERT INTO characters (name, description) VALUES (:name, :description);
+
+selectNameCharLength:
+  SELECT char_length(name) FROM characters;
+
+selectDescriptionCharLength:
+  SELECT char_length(description) FROM characters;

sqldelight-gradle-plugin/src/test/integration-hsql/src/test/kotlin/app/cash/sqldelight/hsql/integration/HsqlTest.kt

@@ -10,7 +10,7 @@ import java.sql.Connection
 import java.sql.DriverManager
 
 class HsqlTest {
-  val conn = DriverManager.getConnection("jdbc:hsqldb:mem:mymemdb")
+  val conn = DriverManager.getConnection("jdbc:hsqldb:mem:mymemdb;shutdown=true")
   val driver = object : JdbcDriver() {
     override fun getConnection() = conn
     override fun closeConnection(connection: Connection) = Unit
@@ -41,4 +41,12 @@ class HsqlTest {
         ),
       )
   }
+
+  @Test fun charLengthFunctionReturnsCharacterCount() {
+    database.charactersQueries.insertCharacter("abcdef", null)
+    val length = database.charactersQueries.selectNameCharLength().executeAsOne()
+    assertThat(length).isEqualTo(6)
+    val nullLength = database.charactersQueries.selectDescriptionCharLength().executeAsOne()
+    assertThat(nullLength.char_length).isNull()
+  }
 }

sqldelight-gradle-plugin/src/test/integration-mysql/src/main/sqldelight/app/cash/sqldelight/mysql/integration/Characters.sq

@@ -0,0 +1,19 @@
+CREATE TABLE characters(
+  name VARCHAR(255) CHARACTER SET utf8mb4 NOT NULL,
+  description TEXT CHARACTER SET utf8mb4
+);
+
+insertCharacter:
+  INSERT INTO characters (name, description) VALUES (:name, :description);
+
+selectNameLength:
+  SELECT length(name) FROM characters;
+
+selectDescriptionLength:
+  SELECT length(description) FROM characters;
+
+selectNameCharLength:
+  SELECT char_length(name) FROM characters;
+
+selectDescriptionCharLength:
+  SELECT char_length(description) FROM characters;

sqldelight-gradle-plugin/src/test/integration-mysql/src/test/kotlin/app/cash/sqldelight/mysql/integration/MySqlTest.kt

@@ -22,6 +22,7 @@ class MySqlTest {
   lateinit var connection: Connection
   lateinit var dogQueries: DogQueries
   lateinit var datesQueries: DatesQueries
+  lateinit var charactersQueries: CharactersQueries
   lateinit var driver: JdbcDriver
 
   @Before
@@ -39,6 +40,7 @@ class MySqlTest {
     MyDatabase.Schema.create(driver)
     dogQueries = database.dogQueries
     datesQueries = database.datesQueries
+    charactersQueries = database.charactersQueries
   }
 
   @After
@@ -123,6 +125,22 @@ class MySqlTest {
     }
   }
 
+  @Test fun lengthFunctionReturnsByteCount() {
+    charactersQueries.insertCharacter("海豚", null)
+    val length = charactersQueries.selectNameLength().executeAsOne()
+    assertThat(length).isEqualTo(6)
+    val nullLength = charactersQueries.selectDescriptionLength().executeAsOne()
+    assertThat(nullLength.length).isNull()
+  }
+
+  @Test fun charLengthFunctionReturnsCharacterCount() {
+    charactersQueries.insertCharacter("海豚", null)
+    val length = charactersQueries.selectNameCharLength().executeAsOne()
+    assertThat(length).isEqualTo(2)
+    val nullLength = charactersQueries.selectDescriptionCharLength().executeAsOne()
+    assertThat(nullLength.char_length).isNull()
+  }
+
   private class ExpectedException : Exception()
   private class SqlDriverTransacter(driver: SqlDriver) : TransacterImpl(driver)
 }