feat: add extract query builders

cmd/go_migrate/build-extract-query.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func buildExtractQueryMssql(job MigrationJob, columns []ColumnType) string {
+	var sbColumns strings.Builder
+
+	if len(columns) == 0 {
+		sbColumns.WriteString("*")
+	} else {
+		for i, col := range columns {
+			sbColumns.WriteString("[")
+			sbColumns.WriteString(col.name)
+			sbColumns.WriteString("]")
+
+			if col.unifiedType == "GEOMETRY" {
+				sbColumns.WriteString(".STAsWKB() AS [")
+				sbColumns.WriteString(col.name)
+				sbColumns.WriteString("]")
+			}
+
+			if i < len(columns)-1 {
+				sbColumns.WriteString(", ")
+			}
+		}
+	}
+
+	return fmt.Sprintf(`SELECT %s FROM [%s].[%s] WITH (NOLOCK)`, sbColumns.String(), job.Schema, job.Table)
+}
+
+func buildExtractQueryPostgres(job MigrationJob, columns []ColumnType) string {
+	var sbColumns strings.Builder
+
+	if len(columns) == 0 {
+		sbColumns.WriteString("*")
+	} else {
+		for i, col := range columns {
+			if col.unifiedType == "GEOMETRY" {
+				sbColumns.WriteString(`ST_AsEWKB("`)
+				sbColumns.WriteString(col.name)
+				sbColumns.WriteString(`") AS "`)
+				sbColumns.WriteString(col.name)
+				sbColumns.WriteString(`"`)
+			} else {
+				sbColumns.WriteString(`"`)
+				sbColumns.WriteString(col.name)
+				sbColumns.WriteString(`"`)
+			}
+
+			if i < len(columns)-1 {
+				sbColumns.WriteString(", ")
+			}
+		}
+	}
+
+	return fmt.Sprintf(`SELECT %s FROM "%s"."%s"`, sbColumns.String(), job.Schema, job.Table)
+}