mssql-lsp

tsql-ls: T-SQL Language Server

A Language Server Protocol (LSP) implementation for T-SQL, forked from sqls and specialized for Microsoft SQL Server.

Features

LSP Capabilities

• Completion — keywords, tables, columns, schemas, joins, system stored procedures, snippets
• Hover — column types, table details, object info
• Go to Definition / Type Definition / Declaration — navigate to CTEs, temp tables, variables, table aliases
• References & Highlights — find all references, document highlights
• Rename & Prepare Rename — safe symbol renaming with preview
• Signature Help — function parameter hints
• Formatting — full document, range, and on-type formatting
• Code Actions — 6 actions (quick fixes for unclosed blocks, remove unused CTEs, surround with TRY/CATCH)
• Diagnostics — 16 rules (unclosed blocks, duplicate variables, undefined variables, unreferenced CTEs, transaction mismatches, and more)
• Folding Ranges — collapse BEGIN/END, TRY/CATCH, IF/ELSE, multi-line comments
• Document & Workspace Symbols — outline view and cross-file symbol search
• Selection Range — smart expand/shrink selection
• Semantic Tokens — full, range, and delta semantic highlighting
• Inlay Hints — inline type annotations
• Linked Editing — synchronized editing of related identifiers

T-SQL Specifics

• [bracket] quoted identifiers
• @variables and @@globals
• #temp and ##global_temp tables
• GO batch separator — all operations are batch-aware
• BEGIN/END, TRY/CATCH, IF/ELSE block parsing

Installation

go install github.com/atornesi/tsql-ls@latest

Configuration

Configuration Methods (in priority order)

1. -config CLI flag
2. workspace/configuration from LSP client
3. $XDG_CONFIG_HOME/sqls/config.yml (defaults to ~/.config/sqls/config.yml)

Configuration File

lowercaseKeywords: false
connections:
  - alias: local_mssql
    driver: mssql
    dataSourceName: "sqlserver://user:password@localhost:1433?database=mydb"
  - alias: individual_mssql
    driver: mssql
    proto: tcp
    user: sa
    passwd: YourPassword
    host: 127.0.0.1
    port: 1433
    dbName: mydb

The first connection in the list is the default.

Editor Setup

Neovim (nvim-lspconfig)

require('lspconfig').sqls.setup {
  cmd = { 'tsql-ls', '-config', vim.fn.expand('~/.config/sqls/config.yml') },
  filetypes = { 'sql' },
  settings = {
    sqls = {
      connections = {
        {
          driver = 'mssql',
          dataSourceName = 'sqlserver://sa:password@localhost:1433?database=mydb',
        },
      },
    },
  },
}

VS Code

Use a generic LSP client extension (e.g., vscode-lsp-sample) pointing to the tsql-ls binary.

Other Editors

Any editor with LSP client support can use tsql-ls. Point the client to the tsql-ls binary with --stdio transport (the default).