diff --git a/apps/desktop/src/components/editor/QueryEditor.vue b/apps/desktop/src/components/editor/QueryEditor.vue
index 1e4c177c72..1ae4fdea7d 100644
--- a/apps/desktop/src/components/editor/QueryEditor.vue
+++ b/apps/desktop/src/components/editor/QueryEditor.vue
@@ -243,6 +243,7 @@ let vimModeComp: import("@codemirror/state").Compartment | null = null;
 let closeBracketsComp: import("@codemirror/state").Compartment | null = null;
 let sqlLanguageComp: import("@codemirror/state").Compartment | null = null;
 let sqlSemanticHighlightComp: import("@codemirror/state").Compartment | null = null;
+let sqlSignatureComp: import("@codemirror/state").Compartment | null = null;
 let codeMirrorCloseBrackets: typeof import("@codemirror/autocomplete").closeBrackets | null = null;
 let codeMirrorCloseBracketsKeymap: readonly import("@codemirror/view").KeyBinding[] | null = null;
 let readOnlyComp: import("@codemirror/state").Compartment | null = null;
@@ -2910,6 +2911,7 @@ onMounted(async () => {
   closeBracketsComp = new Compartment();
   sqlLanguageComp = new Compartment();
   sqlSemanticHighlightComp = new Compartment();
+  sqlSignatureComp = new Compartment();
   codeMirrorCloseBrackets = closeBrackets;
   codeMirrorCloseBracketsKeymap = closeBracketsKeymap;
   readOnlyComp = new Compartment();
@@ -3130,7 +3132,7 @@ onMounted(async () => {
 
   buildSqlSignatureExtension = () =>
     showTooltip.compute(["doc", "selection"], (currentState) => {
-      const signature = getSqlFunctionSignatureHelp(currentState.doc.toString(), currentState.selection.main.head);
+      const signature = getSqlFunctionSignatureHelp(currentState.doc.toString(), currentState.selection.main.head, props.databaseType);
       if (!signature) return null;
       return {
         pos: currentState.selection.main.head,
@@ -3385,7 +3387,7 @@ onMounted(async () => {
         }),
       ),
       hoverTooltip((currentView, pos) => resolveSqlHoverTooltip(currentView, pos)),
-      buildSqlSignatureExtension(),
+      sqlSignatureComp.of(buildSqlSignatureExtension()),
       diagnosticComp.of(buildSqlDiagnosticExtension()),
       createInsertValueHintsExtension({
         isEnabled: () => settingsStore.editorSettings.showInsertValueHints && props.databaseType !== "redis" && props.databaseType !== "mongodb" && props.databaseType !== "elasticsearch",
@@ -3738,9 +3740,10 @@ watch(
 
 watch([() => props.databaseType, () => props.dialect, () => props.syntaxDialect], () => {
   executableStatementRangeCache = null;
-  if (!view.value || !sqlLanguageComp || !buildSqlLanguageExtension || !sqlSemanticHighlightComp || !buildSqlSemanticHighlightExtension) return;
+  if (!view.value || !sqlLanguageComp || !buildSqlLanguageExtension || !sqlSemanticHighlightComp || !buildSqlSemanticHighlightExtension || !sqlSignatureComp || !buildSqlSignatureExtension) return;
+  // Signature tooltips depend on the external dialect, so refresh them even when the document and selection stay unchanged.
   view.value.dispatch({
-    effects: [sqlLanguageComp.reconfigure(buildSqlLanguageExtension()), sqlSemanticHighlightComp.reconfigure(buildSqlSemanticHighlightExtension())],
+    effects: [sqlLanguageComp.reconfigure(buildSqlLanguageExtension()), sqlSemanticHighlightComp.reconfigure(buildSqlSemanticHighlightExtension()), sqlSignatureComp.reconfigure(buildSqlSignatureExtension())],
   });
 });
 
diff --git a/apps/desktop/src/lib/__tests__/editor/queryEditorSqlSignature.spec.ts b/apps/desktop/src/lib/__tests__/editor/queryEditorSqlSignature.spec.ts
new file mode 100644
index 0000000000..38640fef5e
--- /dev/null
+++ b/apps/desktop/src/lib/__tests__/editor/queryEditorSqlSignature.spec.ts
@@ -0,0 +1,19 @@
+import { readFileSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+
+const queryEditorSource = readFileSync(new URL("../../../components/editor/QueryEditor.vue", import.meta.url), "utf8");
+
+describe("QueryEditor SQL signature refresh wiring", () => {
+  it("reconfigures signature help when the database dialect changes", () => {
+    expect(queryEditorSource).toContain('let sqlSignatureComp: import("@codemirror/state").Compartment | null = null;');
+    expect(queryEditorSource).toContain("sqlSignatureComp.of(buildSqlSignatureExtension())");
+
+    const watcherStart = queryEditorSource.indexOf("watch([() => props.databaseType, () => props.dialect, () => props.syntaxDialect]");
+    const watcherEnd = queryEditorSource.indexOf("\n});", watcherStart);
+    const dialectWatcher = queryEditorSource.slice(watcherStart, watcherEnd);
+
+    expect(watcherStart).toBeGreaterThanOrEqual(0);
+    expect(watcherEnd).toBeGreaterThan(watcherStart);
+    expect(dialectWatcher).toContain("sqlSignatureComp.reconfigure(buildSqlSignatureExtension())");
+  });
+});
diff --git a/apps/desktop/src/lib/sql/sqlCompletion.ts b/apps/desktop/src/lib/sql/sqlCompletion.ts
index b8f3200612..f74c0fc0f5 100644
--- a/apps/desktop/src/lib/sql/sqlCompletion.ts
+++ b/apps/desktop/src/lib/sql/sqlCompletion.ts
@@ -954,6 +954,7 @@ const POSTGRES_FUNCTION_SIGNATURES = new Map<string, string[]>([
 ]);
 
 const MYSQL_FUNCTION_SIGNATURES = new Map<string, string[]>([
+  ["CONVERT", ["expression", "type"]],
   ["DATE_FORMAT", ["date", "format"]],
   ["FROM_UNIXTIME", ["unix_timestamp"]],
   ["UNIX_TIMESTAMP", []],
@@ -975,6 +976,7 @@ const SQLITE_FUNCTION_SIGNATURES = new Map<string, string[]>([
 const CLOUDFLARE_D1_FUNCTION_SIGNATURES = new Map(Array.from(SQLITE_FUNCTION_SIGNATURES.entries()).filter(([name]) => name !== "NOW"));
 
 const SQLSERVER_FUNCTION_SIGNATURES = new Map<string, string[]>([
+  ["CONVERT", ["type", "expression"]],
   ["TRY_CAST", ["expression AS type"]],
   ["TRY_CONVERT", ["type", "expression"]],
   ["JSON_VALUE", ["expression", "path"]],
@@ -1619,7 +1621,7 @@ export function getSqlCompletionResultValidFor(sql: string, cursor: number): Reg
   return undefined;
 }
 
-export function getSqlFunctionSignatureHelp(sql: string, cursor: number): SqlFunctionSignatureHelp | null {
+export function getSqlFunctionSignatureHelp(sql: string, cursor: number, databaseType?: DatabaseType): SqlFunctionSignatureHelp | null {
   const beforeCursor = sql.slice(0, cursor);
   const openParenIndex = findActiveFunctionOpenParen(beforeCursor);
   if (openParenIndex == null) return null;
@@ -1628,7 +1630,7 @@ export function getSqlFunctionSignatureHelp(sql: string, cursor: number): SqlFun
   const name = /([A-Za-z_][\w$]*)$/.exec(beforeParen)?.[1]?.toUpperCase();
   if (!name) return null;
 
-  const parameters = SQL_FUNCTION_SIGNATURES.get(name);
+  const parameters = (databaseType ? DATABASE_FUNCTION_SIGNATURES[databaseType]?.get(name) : undefined) ?? SQL_FUNCTION_SIGNATURES.get(name);
   if (!parameters) return null;
 
   const activeParameter = countTopLevelCommas(beforeCursor.slice(openParenIndex + 1));
diff --git a/packages/app-tests/sqlCompletion.test.ts b/packages/app-tests/sqlCompletion.test.ts
index 356109b0b3..2062116aa2 100644
--- a/packages/app-tests/sqlCompletion.test.ts
+++ b/packages/app-tests/sqlCompletion.test.ts
@@ -1782,6 +1782,27 @@ test("returns cast signature with AS syntax", () => {
   });
 });
 
+test("uses dialect-specific argument order for CONVERT completion and signature help", () => {
+  const sql = "select conv";
+  const sqlServerItems = buildSqlCompletionItems(sql, sql.length, {
+    tables: [],
+    columnsByTable: new Map(),
+    databaseType: "sqlserver",
+  });
+  const mysqlItems = buildSqlCompletionItems(sql, sql.length, {
+    tables: [],
+    columnsByTable: new Map(),
+    databaseType: "mysql",
+  });
+
+  assert.equal(sqlServerItems.find((item) => item.label === "CONVERT")?.apply, "CONVERT(${type}, ${expression})");
+  assert.equal(mysqlItems.find((item) => item.label === "CONVERT")?.apply, "CONVERT(${expression}, ${type})");
+
+  const functionSql = "select convert(";
+  assert.deepEqual(getSqlFunctionSignatureHelp(functionSql, functionSql.length, "sqlserver")?.parameters, ["type", "expression"]);
+  assert.deepEqual(getSqlFunctionSignatureHelp(functionSql, functionSql.length, "mysql")?.parameters, ["expression", "type"]);
+});
+
 test("returns null signature help outside function calls", () => {
   assert.equal(getSqlFunctionSignatureHelp("select created_at from users", "select created_at".length), null);
 });