Code

Author: griffio

src/main/kotlin/griffio/Main.kt

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+package griffio
+
+import app.cash.sqldelight.db.QueryResult
+import app.cash.sqldelight.db.SqlDriver
+import app.cash.sqldelight.db.SqlPreparedStatement
+import app.cash.sqldelight.driver.jdbc.JdbcDriver
+import app.cash.sqldelight.driver.jdbc.asJdbcDriver
+import griffio.queries.Sample
+import org.postgresql.copy.CopyManager
+import org.postgresql.core.BaseConnection
+import org.postgresql.ds.PGSimpleDataSource
+import java.io.Reader
+import kotlin.io.path.Path
+import kotlin.io.path.reader
+
+private fun getSqlDriver() = PGSimpleDataSource().apply {
+    setURL("jdbc:postgresql://localhost:5432/laterals")
+    applicationName = "App Main"
+}.asJdbcDriver()
+
+// SqlDelight doesn't expose the generated query directly - only the driver has access to it for execution
+// Create a driver implementation for PostgreSql CopyManager to use the compiled query for execution
+class CopyInManagerDriver(private val driver: JdbcDriver, private val file: Reader) : SqlDriver by driver  {
+    override fun execute(
+        identifier: Int?,
+        sql: String,
+        parameters: Int,
+        binders: (SqlPreparedStatement.() -> Unit)?
+    ): QueryResult<Long> {
+        // CopyManager utility class is the JDBC way to use the COPY command with STDIN
+        // https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/copy/CopyManager.java
+        val copyManager = CopyManager(getSqlDriver().getConnection() as BaseConnection)
+        val copyIn = copyManager.copyIn(sql, file)
+        return QueryResult.Value(copyIn)
+    }
+}
+
+fun main() {
+    val driver = getSqlDriver()
+    val sample = Sample(driver)
+    val copySample = Sample(CopyInManagerDriver(driver, Path("csv/Kickstarter.csv").reader() ))
+    copySample.kickStarterQueries.copy()
+    println(sample.kickStarterQueries.select().executeAsList().joinToString("\n"))
+}

src/main/sqldelight/griffio/migrations/V1__Initial_version.sqm

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+CREATE TABLE Kickstarter_Data (
+    pledged NUMERIC,
+    fx_rate NUMERIC,
+    backers_count INTEGER,
+    launched_at NUMERIC,
+    deadline NUMERIC,
+    goal INTEGER
+);
+
+CREATE TABLE Regions (
+  id INTEGER,
+  name VARCHAR(255)
+);
+
+CREATE TABLE SalesPeople (
+  id INTEGER,
+  full_name VARCHAR(255),
+  home_region_id INTEGER
+);
+
+CREATE TABLE Sales (
+  id INTEGER,
+  amount NUMERIC,
+  product_id INTEGER,
+  salesperson_id INTEGER,
+  region_id INTEGER
+);

src/main/sqldelight/griffio/queries/KickStarter.sq

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+copy:
+COPY Kickstarter_Data (
+    pledged,
+    fx_rate,
+    backers_count,
+    launched_at,
+    deadline,
+    goal
+)
+FROM STDIN
+WITH (FORMAT csv, HEADER TRUE, DELIMITER ',');
+
+select:
+SELECT
+    pledged_usd,
+    avg_pledge_usd,
+    duration,
+    (usd_from_goal / duration) AS usd_needed_daily
+FROM Kickstarter_Data,
+    LATERAL (SELECT pledged / NULLIF(fx_rate, 0) AS pledged_usd) pu,
+    LATERAL (SELECT pledged_usd / NULLIF(backers_count, 0) AS avg_pledge_usd) apu,
+    LATERAL (SELECT goal / NULLIF(fx_rate, 0) AS goal_usd) gu,
+    LATERAL (SELECT goal_usd - pledged_usd AS usd_from_goal) ufg,
+    LATERAL (SELECT (deadline - launched_at) / 86400.00 AS duration) dr;

src/main/sqldelight/griffio/queries/Sales.sq

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+select:
+SELECT
+  sp.id salesperson_id,
+  sp.full_name,
+  sp.home_region_id,
+  rg.name AS home_region_name,
+  home_region_sales.total_sales
+FROM SalesPeople sp
+  JOIN Regions rg ON sp.home_region_id = rg.id
+  JOIN LATERAL (
+    SELECT SUM(amount) AS total_sales
+    FROM Sales s
+    WHERE s.salesperson_id = sp.id
+      AND s.region_id = sp.home_region_id
+  ) home_region_sales ON TRUE;